Migrate from yarn to npm to avoid issues on Windows

Author: rbalaine

.gitignore

@@ -1,10 +1,12 @@
+### VSCode
+.vscode
+### Webstorm
+.idea
 ###> github/gitignore/Node.gitignore ###
 # Logs
 logs
 *.log
 npm-debug.log*
-yarn-debug.log*
-yarn-error.log*
 lerna-debug.log*
 
 # Diagnostic reports (https://nodejs.org/api/report.html)
@@ -66,9 +68,6 @@ typings/
 # Output of 'npm pack'
 *.tgz
 
-# Yarn Integrity file
-.yarn-integrity
-
 # dotenv environment variables file
 .env
 .env.test
@@ -172,10 +171,6 @@ Temporary Items
 # Override: "gatsby files"
 !public
 
-# Yarn Plug'n'Play
-.pnp/
-.pnp.js
-
 # create-react-app build
 /web-app/build/
 

api/.prettierignore

@@ -6,20 +6,20 @@ It is a [RESTful](https://en.wikipedia.org/wiki/Representational_state_transfer)
 
 ## Getting started
 
-This project uses [Yarn](https://yarnpkg.com/) as a dependency manager.
+This project uses [NPM](https://npmjs.com/) as a dependency manager.
 
 To get started, you should first install all dependencies:
 
 ```bash
-yarn
+npm i
 ```
 
 ## Usage
 
 To run the API server, use the `start` script:
 
 ```bash
-yarn start
+npm run start
 ```
 
 The API server listens on port 4000.
@@ -56,17 +56,17 @@ Search for postal code information in the database of valid postal codes.
 To run the API in watch mode:
 
 ```bash
-yarn watch
+npm run watch
 ```
 
 To run the linter against the [standard ESLint config used in Gowento projects](https://github.com/gowento/eslint-config-gowento):
 
 ```bash
-yarn lint
+npm run lint
 ```
 
 To run all tests:
 
 ```bash
-yarn test
+npm run test
 ```