Docs and examples

[hanifshahy]

Provide more examples and add more docs in README.md file.

[DinoLeung]

there's an example here currently, although it's rather minimal.

[paulobreim]

Dino,
Why import 'dart:io'; can´t be used with modal and need changa like import 'dart:io as io' for example?

[DinoLeung]

it can be just import 'dart:io' in the code, but it's just my preference to give an alias so the class name in my telegram models don't conflict with models in io library, e.g. file