Feature: Add Coverage Checking

[jalcine]

I want to help out more with this project but I feel that in order to properly
do so without adding code bloat, coverage checking would be helpful.

[falood]

@jalcine Thank you for this pr, but I'm sorry I don't think it's time to merge it now.
I have a branch here to refactor the whole project, I plan to make coverage check and docs(#85) in this pr.
But I don't have enough time on it, so I still need some time to finish it.

[jalcine]

Ah, okay, that's cool! This doesn't impact master heavily so I think keeping it open until that refactor is done is cool (unless you think closing it is best).

Do you have tasks/features/goals for this refactor? This project is pretty important to me - I'd like to help out.

[falood]

1. modularize codebase (about 85% finished)
   with this feature, people can easy to add custom DSL, such as

    custom_dsl do
    end
    get do
       xxxx
    end
   

2. context variable (this is a break change)
   for now, there're two internal variables conn and params. I want to add another one context what people can get maru router related information from.
   also I don't like hidden variables, maybe use new DSL for endpoints like (haven't decided)

    get :path, fn conn, params, context ->
      xxxx
    end
   
    get :path, &AnotherModule.endpoint_func/3
   

3. use config from custom application and custom the supervisor tree
   for now we have to use config :maru, MY_MODULE to config maru, will add new way like

    defmodule MyAPI do
      use Maru.Router, Application.get_env(:my_app, :my_api)
    end
   

   and provide MyAPI.child_spec function to help use to make maru application under any supervisor tree.

4. Code Style
   complete @spec docs and unit test, move all docs to hexdocs Upload Docs to hexdocs #85
   also format code with elixir 1.6 formatter.

[jalcine]

What is 2?

[falood]

@jalcine I'm really glad to hear what you think about maru, Thank you very much!
Let's keep this pr open, and merge it after the first task modularize codebase merged.

[jalcine]

Awesome - these sounds like good features for maru's longterm success.

[jalcine]

Sorry, I closed this prematurely. Did you merge that modularize codebase branch? IF so, I can begin working to add more tests and make sure coverage is up.