Build a small uploader service module able to upload a file into S3 using Ruby on Rails.
Use Rails 4 and ruby 2.1
Validate using a different modules and including them it into the main one.
Use active record transactions to ensure the actions don’t succeed unless the file upload succeeds and is displayable.
Register the result in a Upload scaffolded resource

Approach this problem as if it is an application going to production. We don't expect it to be perfect (no production code is), but we also don't want you to hack together a throw-away script. This should be representative of something that you would be comfortable releasing to a production environment.

Also, spend whatever amount of time you think is reasonable. You may use whatever gems, frameworks and tools that you think are appropriate, just provide any special setup instructions when you submit your solution.

We are looking for you to demonstrate your knowledge related to common software practices to include reusability, portability and encapsulation - to name a few.