Adding missing env file to emg stack

docker-compose.emg.yml

@@ -62,6 +62,7 @@ services:
         target: /cache-db
     env_file:
       - env/emg.env
+      - env/emg_db.env
       - env/emg_obs.env
     environment:
       INSTANCE_ID: "prism-view-server_cache"