Developer guide

Add a missing data

1. Compose your missing data based of git log pretty formats,
2. Choose a environment variable name linked to this missing data using the prefix GIT_COMMIT_,
3. Update the entrypoint.sh to generate the environment variable content,
   • Adding template format using naming convention TEMPLATE_COMMIT_ prefix and _FORMAT suffix,
   • Use git_log_format method to generate the content of your new environment variable.
4. Update the tests/git_log_format.bats to validate your new environment variable generation,
5. Run npm test to validate your new tests,
6. Update the README.md file to document your new environment variable,
7. Create a new Pull-request to be reviewed.