Support unique when using Sidekiq's delay function
Define which args are used to determine uniqueness.

Addresses a use case where only certain arguments should be used
in determining if the job is unique or not. The default to hash
all arguments is not always preferred.
Update readme regarding unique_args method
Use klass.constantize

- eval is evil
- we realized that Sidekiq adds core extensions to String
  if active_support is not loaded
Adding a travis config and make version a little more restrictive.
Ignore local ruby version
Experimenting with travis
Don't update rubygem version
Use the same config as sidekiq does since it seems to work for them.
Cleanup a bunch of unneeded gems
Forgot about pry, don't need that in tests
Get rid of development gems for jruby compatibility
Update README.md
Merge pull request #12 from wanelo/master

Allow worker to specify which arguments to include in uniquing hash
Merge pull request #11 from gogobot/hotfix/unique

Add support for unique when using Sidekiq's delay function
Close #9
Bump version, modify change log and add contributors
Update README.md
test that duplicates aren't scheduled
jobs which were previously scheduled are allowed to be enqueued