build: add commitlint, husky, lint-staged and commitizen

.travis.yml

@@ -20,7 +20,7 @@ jobs:
         provider: npm
         email: $NPM_EMAIL
         api_key: $NPM_API_KEY
-        # prevent travis to clean build files
+        # prevent travis from cleaning build files
         skip_cleanup: true
         on:
           tags: true
@@ -36,6 +36,6 @@ jobs:
         skip_cleanup: true
         on:
           tags: true
-    - stage: upload coverage
+    - stage: codecov upload
       script: npm test -- --coverage
       after_script: codecov --token=$CODECOV_TOKEN

README.md

@@ -40,9 +40,15 @@ unrepeat(chorus.repeat(3));
 //=> { repeated: 'Because I\'m happy. ', count: 3 }
 ```
 
+## Conributing
+
+PR's are always welcome. There is only one thing to know before contributing. Commit messages must comply with [conventional commits](https://www.conventionalcommits.org). Otherwise [husky](https://github.com/typicode/husky) will complain. :)
+
+Thanks to [commitizen](https://github.com/commitizen), `npm run commit` command can be used to create commit messages complying with conventional commits.
+
 ## Releasing
 
-See the [RELEASING](RELEASING.md) for details.
+See [RELEASING](RELEASING.md) for details.
 
 ## Credits