Add comment with command for running in virtualenv

playbooks/edx-east/create_db_and_users.yml

@@ -4,6 +4,10 @@
 #
 # ansible-playbook -c local -i 'localhost,' create_dbs_and_users.yml -e@./db.yml
 #
+# If running ansible from a python virtualenv you will need a command like the following
+#
+# ansible-playbook -c local -i 'localhost,' create_dbs_and_users.yml -e@./db.yml -e "ansible_python_interpreter=$(which python)"
+#
 # where the content of db.yml contains the following dictionaries
 #
 # database_connection: &default_connection