Update README to use aws-sdk gem rather than aws-s3
Fix a helper method used in refreshing attachments.
Merge pull request #27 from kpopper/develop

Update README to use aws-sdk gem rather than aws-s3
support fingerprint
Merge pull request #38 from jspaper/develop

support fingerprint
Merge pull request #29 from mschulkind/develop

Fix a helper method used in refreshing attachments.
Add after_commit support

If not, application crashes on Heroku.
Merge pull request #1 from florentmorin/patch-1

Patch 1