Set the PATH in the crontab

Without this, the command fails because it can't find `bundle`.
Display all images at /images

I'm planning to implement some kind of search and this feels like a step
toward that.
Use s3cmd to move images

The 's3' gem doesn't appear to know how to deal with folders on S3 so
moving the images takes an increasingly long time as it has to iterate
over every object in s3. The 's3cmd' tool runs much much quicker so I'm
planning to use this instead.