Adding Full Support to Test Against Multiple DB engines.
Accomplished by swapping out database.yml files for the dummy rails instance with en engine specific one.
On Teardown Restore schema to previous state.
Don't hard code id's in testing...
Postgres return a time as Class Time  not ActiveSupport::Timezone.
(Also another static ID)
Fixing Postgres failing spec.
Changing the test to not use the unsorted with with_item_keys call.
When Cleaning Versions ensure they are in the correct order.
use assert_nil vs .nil? (fix for jruby?)
adding testing papertrail section to Readme [skip ci]
Tests to cover changes from cb46e87; Cleaner module should group versions by PaperTrail.timestamp_field
Merge branch 'test-pg-mysql'

Add support for running the test suite with PostgreSQL and MySQL.
Run the test suite with PostgreSQL and MySQL in addition to SQLite when running on Travis.