Link to immediately undo a device deletion
Fix device flash messages
Increase display time of flash messages
Render flash messages always at full width

This improves the appearance of flash messages on the index page
Show image preview during device creation
Field labeled as Image URL
Add a mailer to send nudge emails
Use file delivery strategy for development
Nudge button on device detail page
Nudge button disabled in production
Bump rails version to 3.2.12