docs : requires.io badge added

Author: sepandhaghighi

README.md

@@ -6,6 +6,7 @@
 <a href="https://www.codacy.com/app/sepand-haghighi/Orangetool?utm_source=github.com&amp;utm_medium=referral&amp;utm_content=Moduland/Orangetool&amp;utm_campaign=Badge_Grade"><img src="https://api.codacy.com/project/badge/Grade/ad9374e6e7b24a63b34d6a4f419497ac"/></a>
 <a href="https://scrutinizer-ci.com/g/Moduland/Orangetool/build-status/master"><img src="https://scrutinizer-ci.com/g/Moduland/Orangetool/badges/build.png?b=master"></a>
 <a href="http://www.python.org"><img src="https://img.shields.io/badge/python-3.3%2C3.4%2C3.5%2C3.6-blue.svg"></a>
+<a href="https://requires.io/github/Moduland/Orangetool/requirements/?branch=master"><img src="https://requires.io/github/Moduland/Orangetool/requirements.svg?branch=master" alt="Requirements Status" /></a>
 <a href="https://badge.fury.io/py/orangetool"><img src="https://badge.fury.io/py/orangetool.svg"></a>
 <a href="http://moduland.github.io/Orangetool/doc"><img src="https://img.shields.io/badge/doc-latest-orange.svg"></a>
 <a href="http://www.orangetool.ir"><img src="https://img.shields.io/website-up-down-green-red/http/shields.io.svg?label=website"></a>