SCM classes are used to fetch current revision of your source code from repository and deploy it to target host.
Currently, there two scm’s are implemented:
Based on which scm you use, there are different attributes you can specify to check specific version of the code. For example:
[scm]
url = git://git@myurl.tld/repo.git
[release:stable]
branch = master
[release:unstable]
tag = never-deploy-that