Fixes uninitialized constant PaperTrail::RecordTrail::ActiveRecordError

[evmorov]

Fixes #663.

I didn't found the right place for the spec so I put it in spec/models/thing_spec.rb:

  describe "#touch_with_version", versioning: true do
    let(:thing) { Thing.new(name: "pencil") }

    context "when record isn't persisted" do
      it "raises an error" do
        expect {
          thing.paper_trail.touch_with_version
        }.to raise_error(ActiveRecord::ActiveRecordError, "can not touch on a new record object")
      end
    end

Without the fix the spec would say:

expected ActiveRecord::ActiveRecordError with "can not touch on a new record object",
got #<NameError: uninitialized constant PaperTrail::RecordTrail::ActiveRecordError> with backtrace:
# ./lib/paper_trail/record_trail.rb:402:in `touch_with_version'

It's the exception I had in the app I'm working on. The message doesn't help so I was forced to look into the code.

[jaredbeck]

Thanks Evgeny.