Config

We can have environment specific json files in here. They must have the exact name as the environment.

This is for storing non-secret configuration only. We should still be using environment variables to store secret configs.

Although we use environment variables to store secrets, we still use the config object in our code for all config variables (see below for explanation).

The default.json file stores configuration common to all environments, and null keys so that we know what configs we have available to us. local.json is a file stored on our local machines only (it's in .gitignore). You can use this to store any local configs, secret or not. You can also instead use the .env file.

configuration.ts uses these files to compile a config object for use in the app. It follows the following rules:

1. default.json is read and the config object is created from those variables
2. local.json is read and laid over the top
3. the environment specific json file is read and laid over the top (e.g. staging.json)
4. process.env vars are laid over the top

Any process.env vars that you want to be included in this should be specified in the envsToInclude variable in configuration.ts. They should be the exact lowercase version of the environment variable name.