Add a CONTRIBUTING.md file to guide new contributors

[mulu-ken]

As a potential contributor to the Dapper project, I noticed the absence of a 'CONTRIBUTING.md' file in the repository. This document typically provides guidance to people who are considering contributing to a project and establishes clear expectations for conduct and contribution.
I would suggest creating a 'CONTRIBUTING.md' file that includes at least the following sections:

• How to report a bug
• How to suggest a new feature
• Workflow for submitting pull requests
• Coding conventions and standards
• Link to any related documentation

Please consider this suggestion as it will improve our collaborative experience in Dapper project