Use the devstack env file to launch the forums service

docker-compose.yml

@@ -127,6 +127,8 @@ services:
       BOK_CHOY_LMS_PORT: 18003
       BOK_CHOY_CMS_PORT: 18031
       NO_PYTHON_UNINSTALL: 1
+
+
     image: edxops/edxapp:latest
     ports:
       - "18000:18000"
@@ -158,7 +160,7 @@ services:
       - edxapp_studio_assets:/edx/var/edxapp/staticfiles/
 
   forum:
-    command: bash -c 'source /edx/app/forum/ruby_env source && source /edx/app/forum/forum_env && cd /edx/app/forum/cs_comments_service && while true; do ruby app.rb -o 0.0.0.0 ; sleep 2; done'
+    command: bash -c 'source /edx/app/forum/ruby_env source && source /edx/app/forum/devstack_forum_env && cd /edx/app/forum/cs_comments_service && while true; do ruby app.rb -o 0.0.0.0 ; sleep 2; done'
     container_name: edx.devstack.forum
     depends_on:
       - mongo