Provide More Details about Development Workflow in the README

[gkapfham]

• I have searched the issues of this repo and believe that this is not a duplicate.
• I have read the README.md and believe that my question is not covered.

Issue

It is great that this project already has a CONTRIBUTING.md file. However, it
would be great if we can extend this file so that it includes details about the
development workflow that we follow on this project. For instance, it would be
helpful to contributors if they knew that we followed the GitHub flow model. It
would also be helpful if the CONTRIBUTING.md file gave more details about the
commit message standard that is followed by the developers of CommitCanvas.