```ruby
class IepDocument < ActiveRecord::Base
  belongs_to :student
  validates :file_name, uniqueness: true
end
```

Validate uniqueness across file name / date
user
```ruby
class IepDocument < ActiveRecord::Base
  belongs_to :student
  validates :file_name, uniqueness: { scope: :file_date, message: "one unique file name per date" }
end
```
assistant