Write instructions to setup the project

[lorenzovngl]

Write instructions to setup the project to give people the possibility to develop on their local machines.

[kselena]

@lorenzovngl is this complete or is there something else you needed to add?

[lorenzovngl]

As mentioned in README.md:

TODO: add the instructions to configure the local MySQL database and a Google Maps API key

These two things are missing. I will add them.