Catch more errors

Signed-off-by: Tilman Vatteroth <tilman.vatteroth@tu-dortmund.de>

lib/migrations/20180525153000-user-add-delete-token.js

@@ -4,6 +4,14 @@ module.exports = {
     return queryInterface.addColumn('Users', 'deleteToken', {
       type: Sequelize.UUID,
       defaultValue: Sequelize.UUIDV4
+    }).catch(function (error) {
+      if (error.message.toLowerCase().includes('duplicate column name') ||
+        error.message === 'column "deleteToken" of relation "Users" already exists') {
+        // eslint-disable-next-line no-console
+        console.log('Migration has already run… ignoring.')
+      } else {
+        throw error
+      }
     })
   },