Removed Attachment class since it was a failed attempt for Carrierwave
Useful links for showing how to do testing in Rails
RSpec tests now run properly

Rspec was failing due to broken queries to the database because the valid_attributes hash didn't contain all of the necessary default values needed to query the database. For example, creating a Section was failing in the tests because no value for the number attribute was specified, so it was null, and the database won't allow a null value when creating a Section.