Changed redis "exists" method calls to "exists?"

[matt-may]

Redis "exists" method calls were changed to "exists?" to address a deprecation warning from the redis-rb gem.

Addresses #305.

[coveralls]

Coverage decreased (-19.03%) to 78.938% when pulling 4d9c1dd on matt-may:fix/handle-corner-case-deprecation-warning-from-redis-305 into 41990aa on moove-it:master.

[t27duck]

It's possible the mock-redis gem needs to be bumped for the tests to pass.

Also, since the sidekiq update requires the most recent version of the redis gem which is driving this change, the minimum version of sidekiq may need to be bumped in the gemspec as well.

[iax7]

why this small change has delayed so much from merging?

[akhil-gautam]

@matt-may Are there any plans to get this merged?

[rmm5t]

why this small change has delayed so much from merging?

Because the tests are failing.

It's possible the mock-redis gem needs to be bumped for the tests to pass.

Agreed.

Also, since the sidekiq update requires the most recent version of the redis gem which is driving this change, the minimum version of sidekiq may need to be bumped in the gemspec as well.

I think just the gemspec here needs to be updated.

  s.add_dependency 'redis', '~>= 4.2'

[rmm5t]

See #329 which includes @matt-may's deprecation fix, but also fixes the specs as well while upgrading necessary dependencies.

[marcelolx]

Thanks for the PR @matt-may! I'll be closing this since it has been fixed on #335