Support multi ranges

[davydog187]

Each postgres range type supports whats called a multirange

Every range type has a corresponding multirange type. A multirange is an ordered list of non-contiguous, non-empty, non-null ranges. Most range operators also work on multiranges, and they have a few functions of their own.

E.g.

SELECT '{}'::int4multirange;
SELECT '{[3,7)}'::int4multirange;
SELECT '{[3,7), [8,9)}'::int4multirange;

We should decide if and how we want to support multi ranges, probably under another module prefix, like EctoRange.Multi.Date

[PJUllrich]

@davydog187 sounds like a good idea to me 👍