Rename DataObject::Arel::{Connection => ConnectionAdapter}

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Specify correct Rake tasks for Travis

[ci skip]

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Add initial integration specs for ConnectionAdapter

* Implement #primary_key(table).

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Clean-up an unused and unimplemented method

Signed-off-by: Alex Coles <alex@alexbcoles.com>