Added the ability to change the args based on the exception

I added the ability to change the args based on the exception. See the change to README.md for details about how it's used.
Good point Luke.

`retry_args_for_exception` perhaps?

On Thursday, June 26, 2014, Luke Antins <notifications@github.com> wrote:

> In lib/resque/plugins/retry.rb:
>
> > @@ -158,6 +158,17 @@ def args_for_retry(*args)
> >          args
> >        end
> >
> > +      # @abstract
> > +      # Modify the arguments used to retry the job based on the exception.
> > +      # Use this to do something other than try the exact same job again.
> > +      #
> > +      # @return [Array] new job arguments
> > +      #
> > +      # @api public
> > +      def dynamic_args_for_retry(exception, *args)
>
> The dynamic part of the method name "feels" wrong to me.
>
> Perhaps something like args_for_retry_exception would be clearer?
>
> —
> Reply to this email directly or view it on GitHub
> <https://github.com/lantins/resque-retry/pull/106/files#r14234008>.
>