diff --git a/database/-postponed/2018_07_08_202724_create_table_comments_table.php b/database/-postponed/2018_07_08_202724_create_table_comments_table.php
deleted file mode 100644
index 9b7719f..0000000
--- a/database/-postponed/2018_07_08_202724_create_table_comments_table.php
+++ /dev/null
@@ -1,41 +0,0 @@
-<?php
-
-use Illuminate\Support\Facades\Schema;
-use Illuminate\Database\Schema\Blueprint;
-use Illuminate\Database\Migrations\Migration;
-
-class CreateTableCommentsTable extends Migration
-{
-    /**
-     * Run the migrations.
-     *
-     * @return void
-     */
-    public function up()
-    {
-        Schema::create('table_comments', function (Blueprint $table) {
-            $table->increments('id');
-            $table->timestamps();
-	        $table->unsignedInteger('data_table_id');
-	        $table->unsignedInteger('author_id');
-
-	        $table->foreign('data_table_id')
-		        ->references('id')->on('data_tables')
-		        ->onDelete('cascade');
-
-	        $table->foreign('author_id')
-		        ->references('id')->on('users')
-		        ->onDelete('cascade');
-        });
-    }
-
-    /**
-     * Reverse the migrations.
-     *
-     * @return void
-     */
-    public function down()
-    {
-        Schema::dropIfExists('table_comments');
-    }
-}
diff --git a/database/-postponed/2018_07_08_203424_create_user_follows_table.php b/database/-postponed/2018_07_08_203424_create_user_follows_table.php
deleted file mode 100644
index ad16984..0000000
--- a/database/-postponed/2018_07_08_203424_create_user_follows_table.php
+++ /dev/null
@@ -1,41 +0,0 @@
-<?php
-
-use Illuminate\Support\Facades\Schema;
-use Illuminate\Database\Schema\Blueprint;
-use Illuminate\Database\Migrations\Migration;
-
-class CreateUserFollowsTable extends Migration
-{
-    /**
-     * Run the migrations.
-     *
-     * @return void
-     */
-    public function up()
-    {
-        Schema::create('user_follows', function (Blueprint $table) {
-            $table->increments('id');
-            $table->timestamps();
-	        $table->unsignedInteger('user_id');
-	        $table->unsignedInteger('target_user_id');
-
-	        $table->foreign('user_id')
-		        ->references('id')->on('users')
-		        ->onDelete('cascade');
-
-	        $table->foreign('target_user_id')
-		        ->references('id')->on('users')
-		        ->onDelete('cascade');
-        });
-    }
-
-    /**
-     * Reverse the migrations.
-     *
-     * @return void
-     */
-    public function down()
-    {
-        Schema::dropIfExists('user_follows');
-    }
-}
diff --git a/database/-postponed/2018_07_08_204223_create_table_favourites_table.php b/database/-postponed/2018_07_08_204223_create_table_favourites_table.php
deleted file mode 100644
index 9f1b45e..0000000
--- a/database/-postponed/2018_07_08_204223_create_table_favourites_table.php
+++ /dev/null
@@ -1,42 +0,0 @@
-<?php
-
-use Illuminate\Support\Facades\Schema;
-use Illuminate\Database\Schema\Blueprint;
-use Illuminate\Database\Migrations\Migration;
-
-class CreateTableFavouritesTable extends Migration
-{
-    /**
-     * Run the migrations.
-     *
-     * @return void
-     */
-    public function up()
-    {
-        Schema::create('table_favourites', function (Blueprint $table) {
-            $table->increments('id');
-            $table->timestamps();
-
-	        $table->unsignedInteger('user_id');
-	        $table->unsignedInteger('data_table_id');
-
-	        $table->foreign('user_id')
-		        ->references('id')->on('users')
-		        ->onDelete('cascade');
-
-	        $table->foreign('data_table_id')
-		        ->references('id')->on('data_tables')
-		        ->onDelete('cascade');
-        });
-    }
-
-    /**
-     * Reverse the migrations.
-     *
-     * @return void
-     */
-    public function down()
-    {
-        Schema::dropIfExists('table_favourites');
-    }
-}
diff --git a/database/migrations/2018_07_08_193638_create_data_tables_table.php b/database/migrations/2018_07_08_193638_create_data_tables_table.php
index 35830ec..729b41c 100644
--- a/database/migrations/2018_07_08_193638_create_data_tables_table.php
+++ b/database/migrations/2018_07_08_193638_create_data_tables_table.php
@@ -23,7 +23,6 @@ class CreateDataTablesTable extends Migration
             $table->text('description');
             $table->text('license');
             $table->text('source_link');
-            $table->longText('content');
 
             $table->foreign('owner_id')->references('id')->on('users')
                 ->onDelete('cascade');
diff --git a/database/migrations/2018_07_08_193639_create_changesets_table.php b/database/migrations/2018_07_08_193639_create_changesets_table.php
index 9219fc7..a97261a 100644
--- a/database/migrations/2018_07_08_193639_create_changesets_table.php
+++ b/database/migrations/2018_07_08_193639_create_changesets_table.php
@@ -15,12 +15,13 @@ class CreateChangesetsTable extends Migration
     {
         Schema::create('changesets', function (Blueprint $table) {
             $table->increments('id');
-            $table->timestamp('created_at');
+            $table->timestamps();
             $table->unsignedInteger('data_table_id')->index();
             $table->unsignedInteger('target_revision');
+            $table->text('message');
             $table->boolean('applied');
             $table->unsignedInteger('author_id')->index()->nullable();
-            $table->longText('content'); // incremental changeset including original row values so that it can be reversed
+            $table->jsonb('patch'); // incremental changeset including original row values so that it can be reversed
 
             $table->foreign('data_table_id')->references('id')->on('data_tables')
                 ->onDelete('cascade');
diff --git a/database/migrations/2018_07_12_185431_create_comments_table.php b/database/migrations/2018_07_12_185431_create_comments_table.php
new file mode 100644
index 0000000..5b347b0
--- /dev/null
+++ b/database/migrations/2018_07_12_185431_create_comments_table.php
@@ -0,0 +1,44 @@
+<?php
+
+use Illuminate\Support\Facades\Schema;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Database\Migrations\Migration;
+
+class CreateCommentsTable extends Migration
+{
+    /**
+     * Run the migrations.
+     *
+     * @return void
+     */
+    public function up()
+    {
+        Schema::create('comments', function (Blueprint $table) {
+            $table->increments('id');
+            $table->timestamps();
+            $table->unsignedInteger('ancestor_id')->index()->nullable();
+            $table->unsignedInteger('author_id')->index();
+            $table->unsignedInteger('data_table_id')->index();
+            $table->text('message');
+
+            $table->foreign('data_table_id')->references('id')->on('data_tables')
+                ->onDelete('cascade');
+
+            $table->foreign('author_id')->references('id')->on('users')
+                ->onDelete('cascade');
+
+            $table->foreign('ancestor_id')->references('id')->on('comments')
+                ->onDelete('set null');
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     *
+     * @return void
+     */
+    public function down()
+    {
+        Schema::dropIfExists('comments');
+    }
+}
diff --git a/database/migrations/2018_07_12_185840_create_favourites_table.php b/database/migrations/2018_07_12_185840_create_favourites_table.php
new file mode 100644
index 0000000..9eb7431
--- /dev/null
+++ b/database/migrations/2018_07_12_185840_create_favourites_table.php
@@ -0,0 +1,40 @@
+<?php
+
+use Illuminate\Support\Facades\Schema;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Database\Migrations\Migration;
+
+class CreateFavouritesTable extends Migration
+{
+    /**
+     * Run the migrations.
+     *
+     * @return void
+     */
+    public function up()
+    {
+        Schema::create('favourites', function (Blueprint $table) {
+            $table->increments('id');
+            $table->timestamps();
+
+            $table->unsignedInteger('user_id');
+            $table->unsignedInteger('data_table_id');
+
+            $table->foreign('user_id')->references('id')->on('users')
+                ->onDelete('cascade');
+
+            $table->foreign('data_table_id')->references('id')->on('data_tables')
+                ->onDelete('cascade');
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     *
+     * @return void
+     */
+    public function down()
+    {
+        Schema::dropIfExists('favourites');
+    }
+}
diff --git a/database/-postponed/2018_07_08_203801_create_discussion_follows_table.php b/database/migrations/2018_07_12_190059_create_discussion_follows_table.php
similarity index 65%
rename from database/-postponed/2018_07_08_203801_create_discussion_follows_table.php
rename to database/migrations/2018_07_12_190059_create_discussion_follows_table.php
index cc16aee..37c9c02 100644
--- a/database/-postponed/2018_07_08_203801_create_discussion_follows_table.php
+++ b/database/migrations/2018_07_12_190059_create_discussion_follows_table.php
@@ -16,16 +16,14 @@ class CreateDiscussionFollowsTable extends Migration
         Schema::create('discussion_follows', function (Blueprint $table) {
             $table->increments('id');
             $table->timestamps();
-	        $table->unsignedInteger('user_id');
-	        $table->unsignedInteger('data_table_id');
+            $table->unsignedInteger('user_id');
+            $table->unsignedInteger('data_table_id');
 
-	        $table->foreign('user_id')
-		        ->references('id')->on('users')
-		        ->onDelete('cascade');
+            $table->foreign('user_id')->references('id')->on('users')
+                ->onDelete('cascade');
 
-	        $table->foreign('data_table_id')
-		        ->references('id')->on('data_tables')
-		        ->onDelete('cascade');
+            $table->foreign('data_table_id')->references('id')->on('data_tables')
+                ->onDelete('cascade');
         });
     }
 
diff --git a/database/migrations/2018_07_12_190346_create_content_reports_table.php b/database/migrations/2018_07_12_190346_create_content_reports_table.php
new file mode 100644
index 0000000..6fc48ee
--- /dev/null
+++ b/database/migrations/2018_07_12_190346_create_content_reports_table.php
@@ -0,0 +1,39 @@
+<?php
+
+use Illuminate\Support\Facades\Schema;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Database\Migrations\Migration;
+
+class CreateContentReportsTable extends Migration
+{
+    /**
+     * Run the migrations.
+     *
+     * @return void
+     */
+    public function up()
+    {
+        Schema::create('content_reports', function (Blueprint $table) {
+            $table->increments('id');
+            $table->timestamps();
+            $table->morphs('object');
+            $table->unsignedInteger('author_id')->index();
+            $table->text('message');
+
+            $table->foreign('author_id')->references('id')->on('users')
+                ->onDelete('cascade');
+
+            // we can't add a foreign key constraint on the morph column, need to check manually
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     *
+     * @return void
+     */
+    public function down()
+    {
+        Schema::dropIfExists('content_reports');
+    }
+}
diff --git a/database/migrations/2018_07_12_190830_create_notifications_table.php b/database/migrations/2018_07_12_190830_create_notifications_table.php
new file mode 100644
index 0000000..312ab73
--- /dev/null
+++ b/database/migrations/2018_07_12_190830_create_notifications_table.php
@@ -0,0 +1,41 @@
+<?php
+
+use Illuminate\Support\Facades\Schema;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Database\Migrations\Migration;
+
+class CreateNotificationsTable extends Migration
+{
+    /**
+     * Run the migrations.
+     *
+     * @return void
+     */
+    public function up()
+    {
+        Schema::create('notifications', function (Blueprint $table) {
+            $table->increments('id');
+            $table->timestamps();
+            $table->unsignedInteger('user_id')->index();
+            $table->unsignedInteger('actor_id')->index()->nullable(); // who did it
+            $table->string('action'); // what happened, e.g.: favourited, mentioned, forked, commented
+            $table->nullableMorphs('context'); // the action target or context
+
+            $table->foreign('actor_id')->references('id')->on('users')
+                ->onDelete('cascade');
+
+            $table->foreign('user_id')->references('id')->on('users')
+                ->onDelete('cascade');
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     *
+     * @return void
+     */
+    public function down()
+    {
+        Schema::dropIfExists('notifications');
+    }
+}