Rebuild staging branches script

[Charl1996]

This PR adds the ability for developers to more easily track and rebuild the CommCare Analytics staging branch. At the moment it's very basic.

What's the process?

When you have a feature branch that you want to deploy to staging you should first add it to the scripts/staging.yml file under the branches section and run the command to rebuild the staging branch:

./scripts/rebuildstaging

Note that this will only rebuild the staging branch locally, so afterwards you need to push the staging branch and deploy CCA as we currently do - manually.

How does it work?

Dimagi maintains a pypi package called git-rebuild-branch which this PR is also using. This PR lists it as a dev dependency in the setup.py file, so in order to use it the developer must first run

pip install -e .[dev]

Furthermore, a rebuildingstaging bash script simply invokes the command, which in turns pulls the trunk (in this case master branch) and merge all the listed feature branches into it. All this happens on your local machine of course.

[Charl1996]

Once this goes in I will notify everyone so we can make sure all current feature branch that should be on staging is in.

[kaapstorm]

which in turns pulls the trunk (in this case master branch) and merge all the listed feature branches into it.

This had me a little confused. I think you mean, "which in turns pulls the trunk (in this case master branch), then creates a staging branch, and merges all the listed feature branches into staging."

[Charl1996]

which in turns pulls the trunk (in this case master branch) and merge all the listed feature branches into it.

This had me a little confused. I think you mean, "which in turns pulls the trunk (in this case master branch), then creates a staging branch, and merges all the listed feature branches into staging."

Oh! Totally! You're 100% right, sorry for the confusion!