Git usage guidelines

Some guidelines about git commits and PRs;

• When someone looks at the history of a file or branch, it is the commit messages that they see. Commit messages are an important record.
• Commit summary messages should be descriptive, clear and concise ... a short sentence, not a single word.
• As a rule of thumb, each PR should only contain up to about 10 commits ... if you have more than that then they should either be squashed down or your PR is probably trying to do too much at once.
• It is better to deliver multiple smaller PRs than one big one.