Add dependency.

composer.json

@@ -25,6 +25,7 @@
         "contao-community-alliance/url-builder":"~1.1",
         "netzmacht/php-javascript-builder": "~1.0",
         "netzmacht/php-leaflet": "dev-master",
+        "netzmacht/contao-dev-tools":"~1.0",
         "bit3/contao-meta-palettes": "~1.5",
         "menatwork/contao-multicolumnwizard": "~3.2",
         "doctrine/cache": "~1.0"