add missing dependency to composer.json

Author: iteman

composer.json

@@ -22,6 +22,7 @@
     "require-dev": {
         "phpunit/phpunit": "~4.0",
         "piece/stagehand-testrunner": "~4.1@dev",
+        "symfony/asset": "~2.7",
         "symfony/browser-kit": "~2.7",
         "symfony/filesystem": "~2.7",
         "symfony/http-foundation": "~2.7",
@@ -39,6 +40,7 @@
         }
     },
     "suggest": {
+        "symfony/asset": ">=2.7.0 provides transparent URL rewriting with the `asset()` function in Twig templates",
         "symfony/twig-bridge": ">=2.7.0 provides transparent URL rewriting with the `asset()` function in Twig templates",
         "symfony/twig-bundle": ">=2.7.0 provides transparent URL rewriting with the `asset()` function in Twig templates"
     },