[P] I replicated micrograd in C++ and added more functionality

Hi everyone!

A couple of days ago, I finally decided to follow [Andrej Karpathy's micrograd tutorial](https://www.youtube.com/watch?v=VMj-3S1tku0). I liked the concepts so much I implemented it in C++ and added more functionality:

\- Optimizers: Adam, SGD with momentum
\- Activation functions: tanh, sigmoid, relu

I tried to make both the API as well as internal library as clean as possible so that everyone could understand the basic algorithms behind deep learning. Here is the project's [repo](https://github.com/fszewczyk/shkyera-grad) and a [get started guide](https://fszewczyk.github.io/shkyera-grad/md_docs_tutorials_GetStarted.html). …

adam functions machinelearning relu sigmoid