* Install dotenv package using `npm i dotenv` * Create a new file `.env` and add `MONGODB_URI=mongodb://localhost:27017/blogDB` or your local/remote equivalent * Replace `mongoose.connect("mongodb://localhost:27017/blogDB", {useNewUrlParser: true, useUnifiedTopology: true});` with `mongoose.connect(process.env.MONGODB_URI, {useNewUrlParser: true, useUnifiedTopology: true});` in app.js * Do not forget to add `.env` to `.gitignore` file.