Fibonacci implementation (TODO)

[dmytrostriletskyi]

Hello,

I tried to implement one of TODO points — Fibonacci.

For first step I did two ways of getting Fibonacci sequence — recursion and cache.
If my work seems good, I will add other solutions and extend information.

TODO for current stage of pull request:

• Documentation
• Fibonacci implementations
• Tests

Fibonacci implementations:

• Via golden ratio
• Matrix
• Using memoization
• Using generators
• Using looping technique

[OmkarPathak]

Really great effort. I am looking forward when you will be completing other implementations of fibonacci.