Fix more incompatibilities with Laravel 5.5

framework/core/migrations/2016_02_04_095452_add_slug_to_discussions.php

@@ -20,7 +20,7 @@ return [
         });
 
         // Store slugs for existing discussions
-        $schema->getConnection()->table('discussions')->chunk(100, function ($discussions) use ($schema) {
+        $schema->getConnection()->table('discussions')->chunkById(100, function ($discussions) use ($schema) {
             foreach ($discussions as $discussion) {
                 $schema->getConnection()->table('discussions')->where('id', $discussion->id)->update([
                     'slug' => Str::slug($discussion->title)

framework/core/src/Database/DatabaseMigrationRepository.php

@@ -58,7 +58,8 @@ class DatabaseMigrationRepository implements MigrationRepositoryInterface
         return $this->table()
                 ->where('extension', $extension)
                 ->orderBy('migration', 'asc')
-                ->pluck('migration');
+                ->pluck('migration')
+                ->toArray();
     }
 
     /**