added variables in deploy function usage message

bashrc_overrides/deploy

@@ -5,6 +5,7 @@ deploy() {
   SERVICE="$1"
   if [ "$#" -lt 1 ]; then
     echo "Usage: deploy <service> [service-name]"
+    echo "Variable overrides: REPO_HOST - REPO_ORG - DEPLOY_DIRECTORY"
     return
   fi
   if [ "$#" -gt 1 ]; then