Require Sidekiq Enterprise license credential

[mperham]

Starting with Sidekiq Enterprise 2.0, all customers will need to have valid credentials available in-process when running in production so the software can verify licensing.

• If Bundler is configured according to the documentation, you will need to do nothing. You can check your current Bundler settings by going to your app directory and running:

> bundle config enterprise.contribsys.com
Settings for `enterprise.contribsys.com` in order of priority. The top value will be used
Set for the current user (/Users/mikeperham/.bundle/config): "abcdef12:12345678"

If you have a value there, you should have a value set when the app runs. All good!

• If you are vendoring Sidekiq Enterprise, you will need to either configure Bundler as above or set an environment variable with your credential username:

> SIDEKIQ_ENT_USERNAME=abcdef12 bundle exec sidekiq...

Remember, all of this only applies in production so make sure you verify in production. Sidekiq Enterprise 2.0 will not start without credentials starting in 2020. Until then it will warn if there is a problem.