zero-downtime-migration-example.rb

class MyModel
  def my_column
    if self.has_attribute?(:my_column_JSON)
      self.my_column_JSON
    else
      self.attributes[:my_column]
    end
  end
  
  def my_column=(value)
    if self.has_attribute?(:my_column_JSON)
      self.my_column_JSON = value
    else
      self.attributes = { my_column: value }
    end
  end
end