```ruby
class PopulateFullApprovalWorkflow < ActiveRecord::Migration[5.0]

  class MigrateableCase < ActiveRecord::Base

    self.table_name = :cases

    has_many :approver_assignments,
             -> { approving },
             class_name: 'Assignment',
             foreign_key: :case_id

    has_many :approving_teams,
             -> { where("state != 'rejected'") },
             class_name: BusinessUnit,
             through: :approver_assignments,
             source: :team

    def flagged_for_press_office_clearance?
      approving_teams.include?(BusinessUnit.press_office)
    end

  end

  def up
    MigrateableCase.find_each do |kase|
      if kase.flagged_for_press_office_clearance?
        kase.update(workflow: 'full_approval')
      end
    end
  end

  def down
    execute %/UPDATE cases SET workflow = 'trigger' WHERE workflow = 'full_approval'/
  end
end
```

Fix migration to re-use Case::Base
user
```ruby
class PopulateFullApprovalWorkflow < ActiveRecord::Migration[5.0]

  class Case::Base < ApplicationRecord

    self.table_name = :cases

    has_many :approver_assignments,
             -> { approving },
             class_name: 'Assignment',
             foreign_key: :case_id

    has_many :approving_teams,
             -> { where("state != 'rejected'") },
             class_name: BusinessUnit,
             through: :approver_assignments,
             source: :team

    def flagged_for_press_office_clearance?
      approving_teams.include?(BusinessUnit.press_office)
    end

  end

  def up
    Case::Base.find_each do |kase|
      if kase.flagged_for_press_office_clearance?
        kase.update(workflow: 'full_approval')
      end
    end
  end

  def down
    execute %/UPDATE cases SET workflow = 'trigger' WHERE workflow = 'full_approval'/
  end
end
```
assistant