Contribution guidelines should mention DCO signoff

[tanto259]

PR #15 added some guideline for contribution to the project. However, DCO signoff was not mentioned and it seems that many commits had been manually signed-off.

I would propose that we add DCO signoff as a requirement for future contribution to ensure that those who are submitting work only do so when they have the rights to do so.

This would be as simple as adding the --signoff option to git commit. Furthermore, I would propose the adoption of CONTRIBUTING.md to ensure that all the styles and requirements for contributions are followed.

I will be happy to submit a PR to add these materials :)

[SweetJenn23]

Hey Hartanto! We are looking into this . . . Because we're not working with source code but instead documents, we are needing to discern which apply and which don't. We will keep you posted!! Thanks for this!

[tanto259]

Thanks!

My concern is when we start seeing contributions, we need to make sure that they have the rights to distribute the materials, especially if it came from organizations. Therefore, having DCO signoffs will prevent any possible issues in the future :)

Additionally, I believe the language used in the DCO is "contribution" so it should cover everything.