Add config for iOS cert

Author: andrewsosa

docker-compose.yml

@@ -77,7 +77,7 @@ services:
             - 127.0.0.1:8102:8088
         volumes:
             - ./services/gorush/config.yml:/config.yml
-            - ./services/gorush/Certificates.p12:/certs.p12
+            - ./services/gorush/${IOS_CERT}:/certs.p12
 
     # [Express] Device ID Push Server
     # This service tracks uploaded device IDs and their platform.