Add foreign key to prevent reblogs of non-existent (after race conditions) statuses from happening

Fix issue with detailed status view not supporting unreblogging/unfavouriting

db/migrate/20170217012631_add_reblog_of_id_foreign_key_to_statuses.rb

@@ -0,0 +1,5 @@
+class AddReblogOfIdForeignKeyToStatuses < ActiveRecord::Migration[5.0]
+  def change
+    add_foreign_key :statuses, :statuses, column: :reblog_of_id, on_delete: :cascade
+  end
+end