chore: add coveralls config

.circleci/config.yml

@@ -1,6 +1,8 @@
 # Javascript Node CircleCI 2.0 configuration file
 # Check https://circleci.com/docs/2.0/language-javascript/ for more details
-version: 2
+version: 2.1
+orbs:
+  coveralls: coveralls/coveralls@1.0.6
 jobs:
   build:
     docker:
@@ -34,4 +36,6 @@ jobs:
 
       - run:
           name: Test
-          command: npm run test -- --coverage --coverageReporters=lcov && ./node_modules/codecov/bin/codecov
+          command: npm run test -- --maxWorkers=2 --coverage --coverageReporters=lcov && ./node_modules/codecov/bin/codecov
+
+      - coveralls/upload

README.md

@@ -3,6 +3,7 @@
 > The easiest way to demonstrate your code in action.
 
 [![CircleCI](https://circleci.com/gh/glorious-codes/glorious-demo.svg?style=svg)](https://circleci.com/gh/glorious-codes/glorious-demo)
+[![Coverage Status](https://coveralls.io/repos/github/glorious-codes/glorious-demo/badge.svg?branch=master)](https://coveralls.io/github/glorious-codes/glorious-demo?branch=master)
 
 <p align="center">
   <img width="480" src="https://user-images.githubusercontent.com/4738687/49405334-49505c80-f739-11e8-992e-32f4b6e18311.gif" />