Small doc fix

playbooks/roles/edx_service/tasks/main.yml

@@ -19,7 +19,7 @@
 # Example play:
 #
 # Rather than being included in the play, this role
-# is included as a dependency by other roles in the meta/mail.yml
+# is included as a dependency by other roles in the meta/main.yml
 # file.  The including role should add the following
 # depency definition.
 #
@@ -39,6 +39,9 @@
 #         ...
 #     edx_service_user: hotg_system_user
 #     edx_service_home: "/edx/app/hotg"
+#     edx_service_packages:
+#       debian: [ pkg1, pkg2, pkg3 ]      
+#       redhat: [ pkg4, pkg5 ]
 #
 
 # Generating an ssh key so service users can do a git