Changelog for v3

v3.3

Support {module, function, arguments} tuple to define a cast function instead of type atom.
Added Confex.resolve_env!/1 to populate application environment from system tuples when application is started.

v3.2

Added :system_file adapter, which resolves configuration from contents of a file specified in environment variable, making it easy to read Docker secrets.

v3.1

Adapters list are not hard-coded anymore, now you can use {:via, module} tuple to set an adapter inside the system tuple.

v3.0

Confex is completely redesigned to be adapter-based.
API is changed to be as similar as possible to the Application module.