Adds shippable badge

README.md

@@ -2,6 +2,8 @@
 
 [![Build Status](https://travis-ci.org/perl6/doc.svg?branch=master)](https://travis-ci.org/perl6/doc) [![artistic](https://img.shields.io/badge/license-Artistic%202.0-blue.svg?style=flat)](https://opensource.org/licenses/Artistic-2.0)
 
+[![Run Status](https://api.shippable.com/projects/591e99923f2f790700098a30/badge?branch=master)](https://app.shippable.com/github/perl6/doc) 
+
 An HTML version of this documentation can be found at [https://docs.perl6.org/](https://docs.perl6.org/).
 This is currently the recommended way to consume the documentation.
 
@@ -25,7 +27,7 @@ execution path.
 
 ## Use p6doc
 
-With a Rakudo `perl6` executable in `PATH`, try
+With a Rakudo `perl6` executable in the `PATH`, try
 
     ./bin/p6doc Str