Document Example of Running CommitCanvas on Existing Repository in 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 would be easier and more "predictable" if the README included an example of
how to install and run CommitCanvas as a pre-commit hook for an existing
repository. This would make it possible for a person who wants to learn how to
use the tool to try it out and to produce the expected labels for commits and to
see the rule violations for the commits. Without this type of documentation in
the README file, each individual will have a different experience when they
first try out the tool, perhaps leading them to decide that it does not work
well. While I acknowledge that the ultimate success or failure of the tool
depends on whether it runs well for a person's own repositories, it is worth
having a comprehensive example showing how it works on a specific repository.