Run a given aggregation on a given field.

• Function should be one of the aggregates supported by Ecto: https://hexdocs.pm/ecto/Ecto.Repo.html#c:aggregate/4
• Field should be a numeric field on the User schema

Deactivated users cannot login

Regenerate all the passwords!

Each user will get 16 random bytes of their very own.

Argument will be base16 encoded, so, super safe