Better document pre-requisites

[jwflory]

Summary

Better explain how to use the pre-requisites to run this project

Background

We link to two repos, download_shapefiles_from_gadm and import_shapefiles_to_postgres, without explaining what they are or how to use them. It's unclear what is needed by the user to get those repos set up and working in the context of coordinates_to_admin_id_server.

Details

Preferably, the best solution is to prompt the user to set these pre-requisites up interactively when building this project.

Alternatively, better documentation is needed to explain how to set them up and what the user is expected to have running (or not) when using this repo. Do they need to have another project running? Do they need a Postgres database to already be set up and running?

Outcome

Easier to run the project for the first time, better idea of how to set up a development environment or even run it in a production environment