Fix Mongodb url in forum when running separate service

MONGOHQ_URL was not properly set when MONGODB_HOST/PORT was customised.
That's because the environment variable was being defined in the
Dockerfile, and not at runtime.

Close #267

CHANGELOG.md

@@ -4,6 +4,7 @@ Note: Breaking changes between versions are indicated by "💥".
 
 ## Unreleased
 
+- [Bugfix] Fix MongoDb url in forum when running separate service (#267)
 - 💥[Improvement] Better `dev` commands, with dedicated development docker image. One of the consequences is that the `dev watchthemes` command is replaced by `dev run lms watchthemes`.
 - [Improvement] `images` commands now accept multiple `image` arguments
 

tutor/templates/build/forum/Dockerfile

@@ -46,6 +46,5 @@ ENV SEARCH_SERVER "http://elasticsearch:9200"
 ENV MONGODB_AUTH ""
 ENV MONGODB_HOST "mongodb"
 ENV MONGODB_PORT "27017"
-ENV MONGOHQ_URL "mongodb://$MONGODB_AUTH$MONGODB_HOST:$MONGODB_PORT/cs_comments_service"
 EXPOSE 4567
 CMD ./bin/unicorn -c config/unicorn_tcp.rb -I '.'

tutor/templates/build/forum/bin/docker-entrypoint.sh

@@ -1,5 +1,7 @@
 #!/bin/sh -e
 
+export MONGOHQ_URL="mongodb://$MONGODB_AUTH$MONGODB_HOST:$MONGODB_PORT/cs_comments_service"
+
 echo "Waiting for mongodb/elasticsearch..."
 dockerize -wait tcp://$MONGODB_HOST:$MONGODB_PORT -wait $SEARCH_SERVER/content -wait-retry-interval 5s -timeout 600s
 

tutor/templates/hooks/forum/init

@@ -1,2 +1,4 @@
+export MONGOHQ_URL="mongodb://$MONGODB_AUTH$MONGODB_HOST:$MONGODB_PORT/cs_comments_service"
+
 bundle exec rake search:initialize
 bundle exec rake search:rebuild_index