add docs

Author: vanwhale

lib/resque/failure.rb

@@ -67,6 +67,8 @@ def self.remove(index)
       backend.remove(index)
     end
 
+    # Requeues all failed jobs in a specific queue.
+    # Queue name should be a string.
     def self.requeue_queue(queue)
       i=0
       while job = Resque::Failure.all(i)
@@ -77,11 +79,13 @@ def self.requeue_queue(queue)
       end
     end
 
+    # Removes all failed jobs in a specific queue.
+    # Queue name should be a string.
     def self.remove_queue(queue)
       i=0
       while job = Resque::Failure.all(i)
         if job['queue'] == queue
-          # This will remove from the queue so don't increment the index
+          # This will remove the failure from the array so do not increment the index.
           Resque::Failure.remove(i)
         else
           i+=1