Get list of enum keys or values

[synalysis]

I'm glad I found this module since from my point of view it fills a gap in Elixir - ensure that different modules refer to the same values and don't use atoms like "magic numbers" that hopefully match.

There's just one extension I'd consider useful, for example to be used with Ecto's validate_inclusion() function. If all values (and keys) of an enum could be retrieved for an enum it would avoid the necessity to define an extra constant for this list (as shown in the sample code).

Any opinions on this?