Set attributes to NULL when remove attachment
fix floating point arithmatic with a round
add test case from paperclip
Sets the ContentType whe putting the object in S3
Merge pull request #14 from sillylogger/fix_floats

fix floating point arithmatic with a round
Merge pull request #16 from Jojo-Jojovich/master

Sets the ContentType when putting the object in S3
Merge pull request #15 from walamsyah/fix_clear_attachment

Set attributes to NULL when remove attachment