Have you seen this error on Wercker:
You have reached your pull rate limit. You may increase the limit by authenticating and upgrading: https://www.docker.com/increase-rate-limit"
If you are an occassional/hobby builder then a free account on Docker Hub is all you will need to resolve the issue. Read on for a step-by-step guide.
VALUEas the default value if
$VARis not set or is empty.