Add formatter to the project

[yordis]

• https://hexdocs.pm/mix/master/Mix.Tasks.Format.html

Probably use Travis for checking that people ran the formatter.

[alexdovzhanyn]

Im not sure I understand. Why do people need to run this formatter?

[yordis]

@alexdovzhanyn because you will no need to discuss about code formatting style, it auto fix your code and you keep consistency in your project.

I notice that you dont like to put parenthesis in functions calls (and that is fine) but Elixir suggest you to put parenthesis on functions calls, but if your habit coming from Ruby is not to use you could relay on mix format to do tedious work for you.

It removes friction pretty much, that is why you would use it, the same with credo.

[yordis]

@alexdovzhanyn check how many parenthesis the formatter added for you because you should be using it on the PR