add coverage report

Author: floatdrop

.gitignore

@@ -1 +1,2 @@
 node_modules
+.nyc_output

.travis.yml

@@ -6,3 +6,4 @@ node_js:
   - 'iojs'
   - '0.12'
   - '0.10'
+after_success: npm run coverage

package.json

@@ -13,7 +13,8 @@
     "node": ">=0.10.0"
   },
   "scripts": {
-    "test": "mocha"
+    "test": "nyc mocha",
+    "coverage": "nyc report --reporter=text-lcov | coveralls"
   },
   "files": [
     "index.js"
@@ -25,7 +26,9 @@
     "es6"
   ],
   "devDependencies": {
+    "coveralls": "^2.11.4",
     "mocha": "*",
+    "nyc": "^3.2.2",
     "promises-aplus-tests": "*"
   }
 }

readme.md

@@ -7,7 +7,7 @@
 
 > Itty bitty little widdle twinkie pinkie [ES2015 Promise](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-promise-objects) implementation
 
-[![Build Status](https://travis-ci.org/floatdrop/pinkie.svg?branch=master)](https://travis-ci.org/floatdrop/pinkie)
+[![Build Status](https://travis-ci.org/floatdrop/pinkie.svg?branch=master)](https://travis-ci.org/floatdrop/pinkie) [![Coverage Status](https://coveralls.io/repos/floatdrop/pinkie/badge.svg?branch=master&service=github)](https://coveralls.io/github/floatdrop/pinkie?branch=master)
 
 There are [tons of Promise implementations](https://github.com/promises-aplus/promises-spec/blob/master/implementations.md#standalone) out there, but all of them focus on browser compatibility and are often bloated with functionality.