improve readme, add mdl to build

Makefile

@@ -3,6 +3,7 @@ test:
 
 style:
 	flake8 .
+	mdl README.md
 
 typos:
 	rozental .

README.md

@@ -1,18 +1,30 @@
-It's on
-=======
+# It's on
+
+[![Build Status](https://travis-ci.org/best-doctor/its_on.svg?branch=master)](https://travis-ci.org/best-doctor/its_on)
+[![Maintainability](https://api.codeclimate.com/v1/badges/35e678c4d05199a31eb9/maintainability)](https://codeclimate.com/github/best-doctor/its_on/maintainability)
+[![Test Coverage](https://api.codeclimate.com/v1/badges/35e678c4d05199a31eb9/test_coverage)](https://codeclimate.com/github/best-doctor/its_on/test_coverage)
 
 flag/feature toggle service, written in aiohttp.
 
-API Reference
+## API Reference
 
 ------
 | Method  | Endpoint                   | Description                         |
 | ------- | ---------------------------| ----------------------------------- |
 | `GET`   | `/api/docs`                | Api documentation                   |
 | `GET`   | `/api/v1/switch`           | List of active flags for the group. |
 
-Installing
-------
+## Sample /api/v1/switch output
+
+```json
+
+{
+    "count": 2,
+    "result": ["test_flag3", "test_flag4"]
+}
+```
+
+## Installation
 
 1. Clone repo
     - `$ git clone [email protected]:bestdoctor/public/its_on.git`
@@ -36,16 +48,34 @@ Installing
 1. Open project
     - `open http://localhost:8081/api/docs`
 
-Testing
-------
+## Testing
 
 `$ make test`
 
-Admin
-------
+## Admin
 
 | Endpoint                        | Description                |
 | --------------------------------| -------------------------- |
 | `/zbs/login`                    |  Login form                |
 | `/zbs/switches`                 |  List of flags             |
 | `/zbs/switches/{switch_id}`     |  Flag detail               |
+
+## Contributing
+
+We would love you to contribute to our project. It's simple:
+
+- Create an issue with bug you found or proposal you have.
+  Wait for approve from maintainer.
+- Create a pull request. Make sure all checks are green.
+- Fix review comments if any.
+- Be awesome.
+
+Here are useful tips:
+
+- You can run all checks and tests with `make check`. Please do it
+  before TravisCI does.
+- We use
+  [BestDoctor python styleguide](https://github.com/best-doctor/guides/blob/master/guides/python_styleguide.md).
+  Sorry, styleguide is available only in Russian for now.
+- We respect [Django CoC](https://www.djangoproject.com/conduct/).
+  Make soft, not bullshit.