Loading environment variables #687

Currently Create React App supports environment variables however it leaves some of it to the user's imagination:

Note: Defining environment variables in this manner is temporary for the life of the shell session. Setting permanent environment variables is outside the scope of these docs.

I went on to find my own solution using node-forman but still thought it was sub-optimal*. Is the CRA-team open to leverage dotenv and integrate this in react-scripts (for development)?

Happy to open a PR but wanted to discuss upfront if 👍 or 👎

* I didn't really like wrapping all scripts in a shell script that loads the env variables