Add an explaination to the service directory creation task.

playbooks/roles/edx_service/tasks/main.yml

@@ -56,6 +56,11 @@
     generate_ssh_key=yes
 
 # Assumes that the home directory has been created above.
+# In some cases(vagrant boxes) the home directory gets created
+# but does not have the corrent owner and group. In vagrant for
+# example we were seeing it defaulting it to `root` for both.
+# The item that is a blank string("") ensures the ownership
+# of the home directory is always correct before proceeding.
 - name: create edx_service app, venv, data, and staticfiles dirs
   file: >
     path="{{ edx_service_home }}/{{ item }}"