Support --repo-config flag

[osterman]

what

• Import PR by @darrylb-github
• Support multiple atlantis build manifests per repo

why

• Allows setting different configs for different instances of atlantis, which is useful when wanting to run different servers for production and staging.

use-case

Have separate production and staging Atlantis servers. This enables that by using multiple atlantis.yaml config files in the same repo and setting the --repo-config flag on each server. This allows you to launch a staging Atlantis server pointing at a staging atlantis.yaml file (e.g. --repo-config atlantis-staging.yaml) and a production Atlantis server pointing at a production atlantis.yaml file in the same repo (e.g. --repo-config atlantis-production.yaml).

This way you can use different credentials for staging and production and maintain cleaner separation between environments.

why

• Allow a given atlantis server to watch a specific manifest
• Better multi-account strategy

references

• Adds support for specifying the atlantis.yaml filename on the server side runatlantis/atlantis#310
• closes Implement Support for --repo-config #1

[aknysh]

superseded by #12