Add support for mobile client for server binaries

add support for mobile client for pre-built server binaries tgz

docker-compose.yml

@@ -13,6 +13,8 @@ rocketchat:
     - ROOT=3000
     - ROOT_URL=http://yourhost:3000
     - MONGO_URL=mongodb://mongo:27017/rocketchat
+# uncomment and set the line below if you need to support mobile apps
+#   - DDP_DEFAULT_CONNECTION_URL=http://yourhost:3000
   links:
     - mongo:mongo
   ports: