Create scenario for forking a repository

[EliteMasterEric]

Create a scenario for the following endpoint:

POST /repos/{owner}/{repo}/forks

I'm going to reference CONTRIBUTING and HOW_IT_WORKS, attempt to follow the provided steps, and submit a pull request for this myself.

If I experience any difficulties, I will post about them here, and if I overcome them, I will contribute to the documentation to help others.