set db setting on app also

- db setting is available on db
- app also uses same valiables (eg. MM_USERNAME...)  however there is no hint on compose file.

docker-compose-v1.yml

@@ -22,6 +22,12 @@ app:
     - ./volumes/app/mattermost/config:/mattermost/config:rw
     - ./volumes/app/mattermost/data:/mattermost/data:rw
     - /etc/localtime:/etc/localtime:ro
+  environment:
+  # set same as db environment
+    - MM_USERNAME=mmuser
+    - MM_PASSWORD=mmuser_password
+    - MM_DBNAME=mattermost
+
 web:
   build: web
   ports:

docker-compose.yml

@@ -25,6 +25,11 @@ services:
       - ./volumes/app/mattermost/config:/mattermost/config:rw
       - ./volumes/app/mattermost/data:/mattermost/data:rw
       - /etc/localtime:/etc/localtime:ro
+    environment:
+      # set same as db environment
+      - MM_USERNAME=mmuser
+      - MM_PASSWORD=mmuser_password
+      - MM_DBNAME=mattermost
 
   web:
     build: web