To update the contribution process.

[atugharajohn]

Some of programmers are new and they don't know how to contribute. If we add describe the contribution process step by step, It would help them to contribute easily.

[chinapandaman]

Hey, thanks for posting.

So far I have been pretty much solo developing this project so ya it is definitely an aspect that I overlooked. I’ll need some time though to think about this process as it’s also new to me. There are some plans of adding a developer guide section in the docs if enough people are interested.

[chinapandaman]

Hey, not sure if you still need it but there's now a developer guide in the docs: https://chinapandaman.github.io/PyPDFForm/dev_intro/