Hash keys

Didn’t know hash keys could be arrays. Zang!

EnergyRecord.includes(:case)
            .by_date(Time.now.strftime('%F'))
            .group('cases.case_id', 'HOUR(energy_records.created_at)')
            .maximum(:kwh)

# {["C341", 0]=>1185, ["C341", 1]=>2135, ["C341", 2]=>3220, ...}
# _[["C341", 0]]
# 1185