```ruby
class Drawing < ActiveRecord::Base
  enum status: %i(pending complete)

  validates :image, presence: true
  validates :status, presence: true

  with_options if: :complete? do |complete|
    complete.validates :description, presence: true
    complete.validates :subject_matter, presence: true
    complete.validates :mood_rating, presence: true
    complete.validates :country, presence: true
  end

  validates :age, numericality: { only_integer: true }, allow_nil: true
  validates :mood_rating, numericality: { only_integer: true, greater_than_or_equal_to: 1, less_than_or_equal_to: 10 }, allow_nil: true

  has_attached_file :image, styles: { medium: "640x" }
  validates_attachment_content_type :image, content_type: %r{\Aimage\/.*\Z}

  belongs_to :user

  scope :desc, -> { order("drawings.created_at DESC") }
end
```

Add thumb size to paperclip image styles
user
```ruby
class Drawing < ActiveRecord::Base
  enum status: %i(pending complete)

  validates :image, presence: true
  validates :status, presence: true

  with_options if: :complete? do |complete|
    complete.validates :description, presence: true
    complete.validates :subject_matter, presence: true
    complete.validates :mood_rating, presence: true
    complete.validates :country, presence: true
  end

  validates :age, numericality: { only_integer: true }, allow_nil: true
  validates :mood_rating, numericality: { only_integer: true, greater_than_or_equal_to: 1, less_than_or_equal_to: 10 }, allow_nil: true

  has_attached_file :image, styles: {
    medium: "640x",
    thumb: "100x100#"
  }

  validates_attachment_content_type :image, content_type: %r{\Aimage\/.*\Z}

  belongs_to :user

  scope :desc, -> { order("drawings.created_at DESC") }
end
```
assistant