add coveralls coverage

.travis.yml

@@ -14,3 +14,6 @@ install:
 script:
 - |
     npm run lint && npm run test
+after_success:
+- |
+    cat ./test/unit/coverage/lcov.info | ./node_modules/.bin/coveralls

package.json

@@ -66,6 +66,7 @@
     "chalk": "^1.1.3",
     "cheerio": "^0.22.0",
     "copy-webpack-plugin": "^4.0.1",
+    "coveralls": "^2.13.0",
     "cp-cli": "^1.0.2",
     "cross-env": "^3.1.3",
     "css-loader": "^0.24.0",