add depentency to doctrine/doctrine-bundle (#29)

composer.json

@@ -47,7 +47,8 @@
         "symfony/lock": "^3.4||^4.0",
         "symfony/options-resolver": "^3.4||^4.0",
         "symfony/validator": "^3.4||^4.0",
-        "symfony/yaml": "^3.4||^4.0"
+        "symfony/yaml": "^3.4||^4.0",
+        "doctrine/doctrine-bundle": "^1.0"
     },
     "require-dev": {
         "friendsofphp/php-cs-fixer": "^2.15",