(fix PXP-11163): remove broken codacy badge, add coverage

README.md

@@ -1,8 +1,7 @@
 # Peregrine
 
 [![Build Status](https://travis-ci.org/uc-cdis/peregrine.svg?branch=master)](https://travis-ci.org/uc-cdis/peregrine)
-[![Codacy Badge](https://api.codacy.com/project/badge/Grade/f6128183864d4e5da5093eb72a3c9c97)](https://www.codacy.com/app/uc-cdis/peregrine?utm_source=github.com&utm_medium=referral&utm_content=uc-cdis/peregrine&utm_campaign=Badge_Grade)
-[![Codacy Badge](https://api.codacy.com/project/badge/Coverage/f6128183864d4e5da5093eb72a3c9c97)](https://www.codacy.com/app/uc-cdis/peregrine?utm_source=github.com&utm_medium=referral&utm_content=uc-cdis/peregrine&utm_campaign=Badge_Coverage)
+[![Coverage Status](https://coveralls.io/repos/github/uc-cdis/peregrine/badge.svg)](https://coveralls.io/github/uc-cdis/peregrine)
 
 Query interface to get insights into data in Gen3 Commons