Add coverage badge and speed up tests on Travis

Add code coverage badge to signal code quality.
Limit the max workers to speed up tests on Travis.

See: https://goo.gl/UNQeeQ

.travis.yml

@@ -6,4 +6,5 @@ node_js:
 script:
   - npm run build
   - npm run lint
-  - npm test
+  - npm test -- --maxWorkers=4
+  - npm run coveralls

README.md

@@ -1,5 +1,6 @@
 # css-node-extract
 [![Build Status](https://travis-ci.org/maoberlehner/css-node-extract.svg?branch=master)](https://travis-ci.org/maoberlehner/css-node-extract)
+[![Coverage Status](https://coveralls.io/repos/github/maoberlehner/css-node-extract/badge.svg?branch=master)](https://coveralls.io/github/maoberlehner/css-node-extract?branch=master)
 [![GitHub stars](https://img.shields.io/github/stars/maoberlehner/css-node-extract.svg?style=social&label=Star)](https://github.com/maoberlehner/css-node-extract)
 
 Extract certain nodes from CSS code.

package.json

@@ -13,8 +13,9 @@
     "watch": "npm run clean && tsc -w",
     "clean": "rimraf dist",
     "lint": "tslint src/**/*.ts",
+    "coverage": "jest --coverage --maxWorkers=4",
+    "coveralls": "npm run coverage && cat coverage/lcov.info | coveralls",
     "test": "jest",
-    "coverage": "jest --coverage",
     "prepublishOnly": "npm run build"
   },
   "repository": {
@@ -30,6 +31,7 @@
   },
   "devDependencies": {
     "@types/jest": "^21.1.6",
+    "coveralls": "^3.0.0",
     "jest": "^21.2.1",
     "postcss-less": "^1.1.3",
     "postcss-scss": "^1.0.2",