Add .env.example and always show mock data

[Tona González]

We need to keep track of what environment variables we use, that's why we need an .env.example file, and also for having seed data, we need to display mock data as well.

[Michell Ayala]

Can you list what variables need to be part of the .env file, also, can you add it to the README.md so people know during the setup process what variables are needed?

[Tona González]

Yes, that's a good suggestion, we should add that. as well.