Nanoid port for Elixir Build Status

Elixir port of NanoID (https://github.com/ai/nanoid), a tiny, secure URL-friendly unique string ID generator.

Safe. It uses cryptographically strong random APIs and tests distribution of symbols.

Compact. It uses a larger alphabet than UUID (A-Za-z0-9_-). So ID size was reduced from 36 to 21 symbols.