Added missing ENV variable (#101)

The environment variable that tells the registry to actually use "token" auth was missing.

templates/registry/0/docker-compose.yml

@@ -23,6 +23,7 @@ registry:
   environment:
     REGISTRY_LOG_LEVEL: warn
     REGISTRY_STORAGE_DELETE_ENABLED: true
+    REGISTRY_AUTH: token
     REGISTRY_AUTH_TOKEN_REALM: https://${DOMAIN}:${PPORT}/v2/token
     REGISTRY_AUTH_TOKEN_SERVICE: ${DOMAIN}:${RPORT}
     REGISTRY_AUTH_TOKEN_ISSUER: ${DOMAIN}