Add support for Sidekiq 3.x

[mrnugget]

It seems like the API that delayed_paperclip uses internally doesn't change from Sidekiq 2.x to 3.x. The only thing that changed is that you now have to explicitly require sidekiq/api in the test files to get access to Sidekiq::Queue. Changing require sidekiq to require sidekiq/api seems to work with both Sidekiq versions. At least it works for me locally with and without an update to Sidekiq 3.x.

[ScotterC]

Thanks!

From your knowledge, this is backwards compatible?

[mrnugget]

Yep, the require 'sidekiq/api' works both with Sidekiq 2.x and 3.x.

>> require 'sidekiq/api'
=> true
>> Sidekiq::VERSION
=> "2.17.7"

And the API that delayed_paperclip uses did not change (or otherwise the tests would break, which they do not).

[ScotterC]

Great!

[mrnugget]

Thanks for merging this!