[A21] [EXPERT] installer nodemon pour faciliter le codage

Install nodemon
nodemon is a convenience tool. It will watch the files in the directory it was started in, and if it detects any changes, it will automatically restart your Node application (meaning you don’t have to). In contrast to Express, nodemon is not something the app requires to function properly (it just aids us with development), so install it using:

npm install --save-dev nodemon
This will add nodemon to the dev-dependencies section of the package.json file.

[Andrée-anne]