This was removed from `ROM::Command` as part of the move to 3.x. Data
should be validated before being sent to commands.

See: rom commit 80bb84

The `assert_tuple_count` checking was removed from `ROM::Command`
during the 2.x work. The underlying command no longer performs
this check so the spec was failing.

See: rom commit bec2c4

`ROM::Memory::Dataset` was updated to use `dry-initializer` so the calls
to `option` in dataset here are now updated using the new syntax with
some bonus type checking courtesy of `dry-types`.

See: rom commit 25f937

Support the same ruby versions as other `rom-*` gems.

Provides a `Test` module to the specs to isolate test-specific classes
and objects. This is similar to setup in other rom-* gems.

There were still a few references to repository which are now removed.

Updates the gateway to use the ROM initializer class, which is a thin
wrapper around `dry-initializer` - eliminating some boilerplate and
allow for some type enforcement for params.

Of note, the `options` param was renamed to `csv_options` since
`dry-initializer` *did not like* a param named `options`. Also, the
`datasets` attr reader was moved up to make it a little more obvious.

Updates the `relation_spec` to use the new `Test` module to isolate the
`RelationPlugin` module created for the examples.

Use the new `ROM::CSV::Types` module in the params/options definitions
throughout.

The `execute` method is the only public method exposed by commands at
this time.

Recent changes to `ROM::Memory::Relation` made it possible to use it as
the superclass for adapter relations. This adds schema support among
other things.

Adds `CSV::Storage` to perform the reading and writing to csv files. The
new class is used in the `Dataset` and the `Gateway`. The connection is
passed in to the dataset to keep the command functionality working.