build fixes for nginx, add forum

docker/build/nginx/Dockerfile

@@ -9,7 +9,9 @@ RUN /edx/app/edx_ansible/venvs/edx_ansible/bin/ansible-playbook nginx.yml -c loc
    -i '127.0.0.1,' \
    -e@roles/edxapp/defaults/main.yml \
    -e@roles/xqueue/defaults/main.yml \
-   -e@roles/certs/defaults/main.yml
+   -e@roles/certs/defaults/main.yml \
+   -e@roles/forum/defaults/main.yml
+
 
 RUN echo "\ndaemon off;" >> /etc/nginx/nginx.conf
 WORKDIR /etc/nginx

docker/build/nginx/ansible_overrides.yml

+---
+
+FLOCK_TLD: "edx"

docker/plays/nginx.yml

@@ -14,6 +14,7 @@
       - cms
       - xqueue
       - certs
+      - forum
       nginx_default_sites:
       - lms
       nginx_extra_sites: "{{ NGINX_EDXAPP_EXTRA_SITES }}"