Adding usage, related links and license in README.md

README.md

@@ -1,3 +1,27 @@
 # markdownlint-cli [![Build Status](https://travis-ci.org/igorshubovych/markdownlint-cli.svg?branch=master)](https://travis-ci.org/igorshubovych/markdownlint-cli)
 
-> Command Line Interface for [MarkdownLint](https://github.com/DavidAnson/markdownlint)
+> Command Line Interface for [MarkdownLint](https://github.com/DavidAnson/markdownlint)
+
+## Usage
+
+```
+$ markdownlint --help
+
+  Usage: markdownlint [options] <files>
+
+  MarkdownLint Command Line Interface
+
+  Options:
+
+    -h, --help                 output usage information
+    -V, --version              output the version number
+    -c, --config [configFile]  Configuration file
+```
+
+## Related
+
+- [markdownlint](https://github.com/DavidAnson/markdownlint) - API for this module
+
+## License
+
+MIT © Igor Shubovych