Merge pull request #92 from rohith-jayaraman/master

fixes issue #90 by adding message param for custom message in bump.rb

lib/gem/release/cmds/bump.rb

@@ -76,7 +76,7 @@ class Bump < Base
           opts[:commit] = value
         end
 
-        opt '-m', '--message', descr(:message) do |value|
+        opt '-m', '--message MESSAGE', descr(:message) do |value|
           opts[:message] = value
         end