some good resources:
- https://course.fast.ai/index.html
- https://ml-cheatsheet.readthedocs.io/en/latest/index.html
- https://forums.fast.ai/
- https://www.deeplearningbook.org/
to do:
- improve 'learn' function and separate it out into several functions
- cross entropy cost
- better initializations of weights and biases (maybe)
- automatic optimized initialization of learning rate
- adam optimzer