Replace npm with yarn

Closes #156

Author: kunalkapadia

.travis.yml

@@ -2,15 +2,13 @@ language: node_js
 node_js:
   - "4.6"
   - "6.9"
-  - "7.0"
+  - "7.2"
 services:
   - mongodb
 cache:
   directories:
   - node_modules
 git:
   depth: 3
-before_script:
-  - npm prune
 after_script:
-  - npm run report-coverage
+  - yarn report-coverage

README.md

@@ -25,7 +25,7 @@ Heavily inspired from [Egghead.io - How to Write an Open Source JavaScript Libra
 | Authentication via JsonWebToken                  	 	 | Supports authentication using [jsonwebtoken](https://www.npmjs.com/package/jsonwebtoken).  |
 | Code Linting               			 | JavaScript code linting is done using [ESLint](http://eslint.org) - a pluggable linter tool for identifying and reporting on patterns in JavaScript. Uses ESLint with [eslint-config-airbnb](https://github.com/airbnb/javascript/tree/master/packages/eslint-config-airbnb), which tries to follow the Airbnb JavaScript style guide.                                                                                                |
 | Auto server restart                  	 | Restart the server using [nodemon](https://github.com/remy/nodemon) in real-time anytime an edit is made, with babel compilation and eslint.                                                                                                                                                                            |
-| ES6 Code Coverage via [istanbul](https://www.npmjs.com/package/istanbul)                  | Supports code coverage of ES6 code using istanbul and mocha. Code coverage reports are saved in `coverage/` directory post `npm test` execution. Open `coverage/lcov-report/index.html` to view coverage report. `npm test` also displays code coverage summary on console. Code coverage can also be enforced overall and per file as well, configured via .istanbul.yml                                                                                                                                                                            |
+| ES6 Code Coverage via [istanbul](https://www.npmjs.com/package/istanbul)                  | Supports code coverage of ES6 code using istanbul and mocha. Code coverage reports are saved in `coverage/` directory post `yarn test` execution. Open `coverage/lcov-report/index.html` to view coverage report. `yarn test` also displays code coverage summary on console. Code coverage can also be enforced overall and per file as well, configured via .istanbul.yml                                                                                                                                                                            |
 | Debugging via [debug](https://www.npmjs.com/package/debug)           | Instead of inserting and deleting console.log you can replace it with the debug function and just leave it there. You can then selectively debug portions of your code by setting DEBUG env variable. If DEBUG env variable is not set, nothing is displayed to the console.                       |
 | Promisified Code via [bluebird](https://github.com/petkaantonov/bluebird)           | We love promise, don't we ? All our code is promisified and even so our tests via [supertest-as-promised](https://www.npmjs.com/package/supertest-as-promised).                       |
 | API parameter validation via [express-validation](https://www.npmjs.com/package/express-validation)           | Validate body, params, query, headers and cookies of a request (via middleware) and return a response with errors; if any of the configured validation rules fail. You won't anymore need to make your route handler dirty with such validations. |
@@ -44,41 +44,46 @@ git clone [email protected]:KunalKapadia/express-mongoose-es6-rest-api.git
 cd express-mongoose-es6-rest-api
 ```
 
+Install yarn:
+```js
+npm install -g yarn
+```
+
 Install dependencies:
 ```sh
-npm install
+yarn
 ```
 
 Start server:
 ```sh
 # Start server
-npm start
+yarn start
 
 # Selectively set DEBUG env var to get logs
-DEBUG=express-mongoose-es6-rest-api:* npm start
+DEBUG=express-mongoose-es6-rest-api:* yarn start
 ```
 Refer [debug](https://www.npmjs.com/package/debug) to know how to selectively turn on logs.
 
 
 Tests:
 ```sh
 # Run tests written in ES6 along with code coverage
-npm test
+yarn test
 
 # Run tests on file change
-npm run test:watch
+yarn test:watch
 
 # Run tests enforcing code coverage (configured via .istanbul.yml)
-npm run test:check-coverage
+yarn test:check-coverage
 ```
 
 Lint:
 ```sh
 # Lint code with ESLint
-npm run lint
+yarn lint
 
 # Run lint on any file change
-npm run lint:watch
+yarn lint:watch
 ```
 
 Other gulp tasks:
@@ -94,13 +99,13 @@ gulp
 
 ```sh
 # compile to ES5
-1. npm run build
+1. yarn build
 
 # upload dist/ to your server
 2. scp -rp dist/ user@dest:/path
 
 # install production dependencies only
-3. npm i --production
+3. yarn --production
 
 # Use any process manager to start your services
 4. pm2 start dist/index.js
@@ -122,10 +127,10 @@ Logs stacktrace of error to console along with other details. You should ideally
 ![Error logging](https://cloud.githubusercontent.com/assets/4172932/12563361/fb9ef108-c3cf-11e5-9a58-3c5c4936ae3e.JPG)
 
 ## Code Coverage
-Get code coverage summary on executing `npm test`
+Get code coverage summary on executing `yarn test`
 ![Code Coverage Text Summary](https://cloud.githubusercontent.com/assets/4172932/12827832/a0531e70-cba7-11e5-9b7c-9e7f833d8f9f.JPG)
 
-`npm test` also generates HTML code coverage report in `coverage/` directory. Open `lcov-report/index.html` to view it.
+`yarn test` also generates HTML code coverage report in `coverage/` directory. Open `lcov-report/index.html` to view it.
 ![Code coverage HTML report](https://cloud.githubusercontent.com/assets/4172932/12625331/571a48fe-c559-11e5-8aa0-f9aacfb8c1cb.jpg)
 
 ## A Boilerplate-only Option

package.json

@@ -6,17 +6,18 @@
   "main": "index.js",
   "private": false,
   "engines": {
-    "node": ">=4.6.x",
-    "npm": ">=2.15.x"
+    "node": ">=4.6.0",
+    "npm": ">=2.15.9",
+    "yarn": ">=0.17.9"
   },
   "scripts": {
     "start": "gulp serve",
     "build": "gulp",
     "lint": "esw *.js server config --color",
-    "lint:watch": "npm run lint -- --watch",
+    "lint:watch": "yarn lint -- --watch",
     "test": "NODE_ENV=test babel-node node_modules/.bin/isparta cover _mocha -- --ui bdd --reporter spec --colors --compilers js:babel-core/register ./server/**/*.test.js",
-    "test:watch": "npm run test -- --watch",
-    "test:check-coverage": "npm run test && istanbul check-coverage",
+    "test:watch": "yarn test -- --watch",
+    "test:check-coverage": "yarn test && istanbul check-coverage",
     "report-coverage": "coveralls < ./coverage/lcov.info"
   },
   "repository": {
@@ -89,7 +90,7 @@
   "license": "MIT",
   "config": {
     "ghooks": {
-      "pre-commit": "npm run lint && npm test"
+      "pre-commit": "yarn lint && yarn test"
     },
     "commitizen": {
       "path": "./node_modules/cz-conventional-changelog"