Switch to release/development branching model

[cimnine]

Current Behavior

Currently, the master branch is where development happens, and which PRs usually target.
But it's also the branch where all the Docker images are built from.

This leads to situations, where we merge PRs to the master branch, and - when not immediately releasing the branch - the Docker images are getting tagged with a wrong version.

Expected Behavior

The version, which the label on the Docker image portraits, must always be accurate. This helps debugging any issues.

Therefore I suggest the following change of the development workflow:

• The main branch continues to be the master branch. It must be stable. People clone this branch to get started with the Netbox Docker project. The Docker images continue to be built from this branch.
• We introduce a develop branch (like the Netbox project already has) to which we continually merge PRs and on which new features are developed and tested. Whenever we decide it's time for a release, we adjust the VERSION file to x.y.z, merge develop to master, tag that merge-commit with the VERSION number, and finally adjust the VERSION file on the develop branch to x.y.z+1-develop.

[cimnine]

I'm thinking about ditching the name master for the main branch and using stable or release instead.

[tobiasge]

I would use release and develop 👍

[cimnine]

• I've pushed two branches, release & develop
• I've set up branch protection rules
• I've updated the Release wiki page
• I've created an explanation for the Branching Model on the wiki
• I've changed all PRs to target the develop branch
• I've created a PR to adapt the relevant repository files Prepares scripts and documentation for #184 #202
• Configured builds on the Docker Hub to also build the release branch. (No images should get pushed to the registry until Prepares scripts and documentation for #184 #202 is merged to release. And then the master builds should not be pushed anymore.)

What's left to do:

• Merge Prepares scripts and documentation for #184 #202
• Make a release, i.e. merge Release 0.20.0 #212 and create a tag 0.20.0.
• Remove the builds on Docker Hub that target the master branch
• Remove the master branch

[rasanentimo]

Please point the default branch to 'release' instead of 'develop'. It's a bit confusing the follow the guide and not get working environment, for example due to non-working develop branch.

[cimnine]

Please point the default branch to 'release' instead of 'develop'. It's a bit confusing the follow the guide and not get working environment, for example due to non-working develop branch.

First, there's good new for you:
We will eventually revert to that behavior if we merge and release #214.

In the meantime, existing users should not be affected, since there is still a master branch. Once 0.20.0 is merged, people should update to the release branch. Any further git pull will be on the release branch.

The only concern is new users. For them, we have updated the instructions to clone the project to the following command. It causes the release branch to be automatically checked out. So if people follow the guide, they will get it right.

git clone -b release https://github.com/netbox-community/netbox-docker.git

Edit: The wiki page Getting Started pointed to master, which is still around and which is stable. I have updated the instructions there as well to point to release, which already works right now and will continue working after 0.20.0 is released.