#32 Explain in README that project name must be unique and show example error message to help troubleshoot the issue

[vlad-ro]

[crsimmons]

Hi @vlad-ro.

We actually already have a story in our backlog to make this error friendlier. Its currently set to be pointed next week then hopefully picked up soon after.

Your description isn't quite right. The deployment name doesn't need to be globally unique amongst all concourse-up deployments - it just needs to be unique amongst concourse-up deployments in your region. The config bucket is named using both the deployment name and the region

If you want to adjust your description to reflect this and squash everything into one commit then we can merge it.