Removes coveralls hook, adds codecov badge

.travis.yml

@@ -4,6 +4,5 @@ jdk:
     - oraclejdk8
 
 after_success:
-- ./gradlew jacocoTestReport coveralls
 - bash <(curl -s https://codecov.io/bash)
 - python <(curl -s https://raw.githubusercontent.com/TouK/sputnik-ci/master/sputnik-ci.py)

README.md

@@ -2,7 +2,7 @@
 
     Never miss any blog post from developers around JVM in Poland :)
 
-[![Build Status](https://travis-ci.org/jvm-bloggers/jvm-bloggers.svg?branch=master)](https://travis-ci.org/jvm-bloggers/jvm-bloggers)  [![Coverage Status](https://coveralls.io/repos/jvm-bloggers/jvm-bloggers/badge.svg?branch=master&service=github)](https://coveralls.io/github/jvm-bloggers/jvm-bloggers?branch=master) [![Version Eye](https://www.versioneye.com/user/projects/5798bd4874848d004b927ac7/badge.svg)](https://www.versioneye.com/user/projects/5798bd4874848d004b927ac7) [![Slack Status](https://jvm-bloggers-slack.herokuapp.com/badge.svg)](https://jvm-bloggers-slack.herokuapp.com) [![Sputnik](https://sputnik.ci/conf/badge)](https://sputnik.ci/app#/builds/jvm-bloggers/jvm-bloggers)
+[![Build Status](https://travis-ci.org/jvm-bloggers/jvm-bloggers.svg?branch=master)](https://travis-ci.org/jvm-bloggers/jvm-bloggers)  [![codecov](https://codecov.io/gh/jvm-bloggers/jvm-bloggers/branch/master/graph/badge.svg)](https://codecov.io/gh/jvm-bloggers/jvm-bloggers) [![Version Eye](https://www.versioneye.com/user/projects/5798bd4874848d004b927ac7/badge.svg)](https://www.versioneye.com/user/projects/5798bd4874848d004b927ac7) [![Slack Status](https://jvm-bloggers-slack.herokuapp.com/badge.svg)](https://jvm-bloggers-slack.herokuapp.com) [![Sputnik](https://sputnik.ci/conf/badge)](https://sputnik.ci/app#/builds/jvm-bloggers/jvm-bloggers)
 
 ## Overview