Nest: Improve CONTRIBUTING.md

[jmcdo29]

I'm submitting a...

[ ] Regression 
[ ] Bug report
[ ] Feature request
[X] Documentation issue or request (new chapter/page)
[ ] Support request => Please do not submit support request here, instead post your question on Stack Overflow.

Current behavior

There is no Contributing Section

Expected behavior

There is a section in the docs about contributing.

What is the motivation / use case for changing the behavior?

After recently picking up a small ticket to help contribute to NestJS I had to reach out to members of the core team about how to test changes and see how things can be done. There were overall, a couple of hoops I had to jump through (or so it felt) to make sure that I could play with the changes I was currently making. I figured having a section in the docs, maybe under the FAQ section, could help those of us who want to get into helping with this amazing framework and it can point out a couple of practices that should be used when contributing (i.e. using npm link or creating a sample project in an ignored directory, how to run all tests, etc.)

This may also be a good way to help more people feel less intimidated by Nest, as it is a large project with a really complex backend.

Others:

As I recently went through contributing I would definitely be willing to help point out pain points I encountered and help make the docs more clear for other beginners.

[kamilmysliwiec]

I think that we should just update https://github.com/nestjs/nest/blob/master/CONTRIBUTING.md file to keep all advices/hints/info in one single place. Adding a dedicated chapter to the docs doesn't make too much sense. Similarly, Angular has contribute page which simply contains links to the corresponding CONTRIBUTING.md files.

[jmcdo29]

Fair enough. Should the PR be made against the main repository and I'll let you handle spreading it to the others, or should want repo get their own PR?

[kamilmysliwiec]

Let me move this issue. PRs are more than welcome :)