📚 Add status badge

Author: Vincent Langlet

README.md

@@ -1,5 +1,7 @@
 # Symfony3 Custom PHP CodeSniffer Coding Standard
 
+[![CircleCI](https://circleci.com/gh/VincentLanglet/Symfony3-custom-coding-standard.svg?style=svg&circle-token=04bcfbcceb34f9644561c0a9ef27e935ff467705)](https://circleci.com/gh/VincentLanglet/Symfony3-custom-coding-standard)
+
 Documentation
 -------------
   * [Coding Standard](docs/standards.md)