Merge pull request #13 from dipcode-software/feat/docs

Added documentation badge.

Author: srtab

README.md

@@ -2,6 +2,7 @@
 [![Build Status](https://travis-ci.org/dipcode-software/php-form.svg?branch=master)](https://travis-ci.org/dipcode-software/php-form)
 [![Coverage Status](https://coveralls.io/repos/github/dipcode-software/php-form/badge.svg?branch=master)](https://coveralls.io/github/dipcode-software/php-form?branch=master)
 [![Latest Stable Version](https://poser.pugx.org/dipcode/php-form/v/stable)](https://packagist.org/packages/dipcode/php-form)
+[![Documentation](https://alexandriadocs.io/projects/php-form/badge-url/?style=flat)](https://alexandriadocs.io/docs/php-form/index.html)
 [![License](http://img.shields.io/badge/license-MIT-brightgreen.svg?style=flat)](http://www.opensource.org/licenses/MIT)
 
 Full featured form engine library inspired in Django Framework.