diff --git a/composer.json b/composer.json
index 353607d..e837ea6 100644
--- a/composer.json
+++ b/composer.json
@@ -26,5 +26,10 @@
     "require-dev": {
         "friendsofphp/php-cs-fixer": "^1.6",
         "phpspec/phpspec": "^3.0"
+    },
+    "extra": {
+        "branch-alias": {
+            "dev-master": "2.1-dev"
+        }
     }
 }