s3 config

I searched a lot of the documentation on how to do it: there was not much of a drastic change to what was there based on the advice. The form seems to have all that is necessary. Adding a reference to the aws bucket seemed like the only real change and the use of the aws-sdk gem

Some called for a creation of an s3.yml file in the config directory (instead of putting the s3 paperclip info in the production.rb env file) and putting some other attributes such as s3 credentials in the          has_attached_file method       in the image model.

Another thing that was suggested was including a :path attribute in the has_attached_file method such as below:
  :path => "appname/:attachment/:style/:id.:extension"

the heroku guide did not specify that so I ommitted it but kept a note of it as an option if this doesnt work.

Anyway the branch is here