Separating the map_args functionaliy from redis_key

[spight-zz]

Separating the map_args functionality away from redis_key method in order to allow the user to easily redefine the hashed args.

For example, I have a job that accepts certain information about the original user:

def self.perform(approval_id, approver_id)
  ...
end

But I want the job to be unique only by the approval_id parameter. The solution after my change would be to simply overwrite map_args:

def self.map_args(args)
  args[0]
end

[jamiemccarthy]

I'd probably rename the helper method encode_args, or maybe canonicalize_args, because that describes what it does instead of how it does it.

Then this would become:

Suggested change

	args = map_args(args)
	digest = Digest::MD5.hexdigest(encode(class: job, args: args))
	digest = Digest::MD5.hexdigest(encode({ class: job, args: encode_args(args) }))