Don't rely on keys in Aggregator#count
Fix semantic errors in integration spec relations

Given that :events contain a FK pointing to :companies and that
:instructions contain a FK pointing to :employments, make sure that we
only count tuples in the appropriately restricted and joined relations.
Fix alignment in Gemfile
Sync devtools and add rspec dev dependency

Also bump bundler dev dependency
Fix expectations for raised exceptions
Rename Ramom::{Aggregator => Aggregate}
Simplify {Command, Query} definition & registration

* Instantiate all operation *instances* at boot time
* Support defining operations with blocks
Expose Operation::Result

Nuke leftover Database namespace