Add Coveralls support.

.gitignore

@@ -1 +1,3 @@
-node_modules
+/.nyc_output/
+/coverage/
+/node_modules/

.travis.yml

@@ -10,6 +10,12 @@ node_js:
   - "8"
   - "10"
 
+script:
+  - npm run test:cov
+
+after_success:
+  - if [[ "$TRAVIS_NODE_VERSION" = "10" ]]; then npm run coveralls; fi
+
 cache:
   directories:
     - node_modules

README.md

@@ -3,6 +3,7 @@
 [![NPM version](https://img.shields.io/npm/v/staticify.svg)](https://www.npmjs.com/package/staticify)
 [![Linux Build Status](https://img.shields.io/travis/errorception/staticify/master.svg?label=Linux%20build)](https://travis-ci.org/errorception/staticify)
 [![Windows Build status](https://img.shields.io/appveyor/ci/rakeshpai/staticify/master.svg?label=Windows%20build)](https://ci.appveyor.com/project/rakeshpai/staticify/branch/master)
+[![Coverage Status](https://img.shields.io/coveralls/github/errorception/staticify/master.svg)](https://coveralls.io/github/errorception/staticify?branch=master)
 [![dependencies Status](https://img.shields.io/david/errorception/staticify.svg)](https://david-dm.org/errorception/staticify)
 [![devDependencies Status](https://img.shields.io/david/dev/errorception/staticify.svg)](https://david-dm.org/errorception/staticify?type=dev)