Remove Training Resources Model

[dcollie2]

DESCRIPTION

An earlier version of the requirements had training resources stored in their own model. A good bit of this work was completed. Some of that work will be used in Task #72 but once that task is complete, we need to remove the Training Resources model and all related code that is not being used by the has_many_attached association on Topics.

See the PR that added the Training Resources.

DEPENDENCY

Dependent on Training Resources Changed to Topic Document Attachments #72

TASKS

• Remove the model
• Remove the controller
• Remove the route
• Remove the views
• Remove the tests
• Remove the navigation link from the sidebar
• Add a migration to drop the Training Resources table
• Confirm that all tests pass and that nothing was removed that affects Training Resources Changed to Topic Document Attachments #72