Documentations?

**Is your feature request related to a problem? Please describe.**
I believe a lot of users would benefit of clearer documentations on which methods actually exist and how to use them. This is not so clear from the README, and there are numerous nuances in applications which we do not cover, and may result in end users having a hard time getting this to work.

**Describe the solution you'd like**
For a different python package I am developing, I created documentations and hosted it for free on [ReadTheDocs](https://gradientaccumulator.readthedocs.io/en/latest/?badge=latest). This is extremely easy to do. And I setup all the logic necessary for this to work.

However, in order for me to setup, test, and deploy the documentations, it would be nice if I had suitable permissions.
Alternatively, @carloalbertobarbano or someone would create a user at [ReadTheDocs](https://gradientaccumulator.readthedocs.io/en/latest/?badge=latest) (can link to GitHub account), and link this repo to a ReadTheDocs project. That way deployment of docs should work seemlessly.

I can start making the PR now. I will add a `docs/` directory the repo where all relevant information should lie. I will also use autodocs to build the API documentation, which will be parsed based on class/method descriptions in the code base.