Update CONTRIBUTING.md

[Dhaiwat10]

Encountered a few problems while getting started as a new contributor for this project. I'd like to volunteer & setup a contributing doc that'll help onboard new contributors.

[Cali93]

That would be great! Thanks @Dhaiwat10.
Let me know if you need any help/info

[damianmarti]

@Dhaiwat10 did you had time to work on it? I'm setting up the project too and I'm getting an error on the backend. I need to set the dbUrl in .env but I didn't find any information from it on the README.

[damianmarti]

oh, sorry @Dhaiwat10 , I just saw the PR...

[Dhaiwat10]

No worries @damianmarti let me know if you need help setting stuff up! I'm Dhaiwat10#1259 on Discord :))