composer instructions, stability beta

Author: cebe

README.md

@@ -15,7 +15,7 @@ This application template consists of 3 application tiers:
 
 ## Setup
 
-    composer create-project cebe/yii2-app-api my-api
+    composer create-project --stability=beta cebe/yii2-app-api my-api
     cd my-api
     cp env.php.dist env.php