migrating away from paperclip - finding all models

models_with_files = ActiveRecord::Base.descendants.reject(&:abstract_class?).inject({}) do |reducer, model|
  columns = model.column_names.map { |c| $1 if c =~ /(.+)_file_name$/ }.compact
  if columns.size > 0
    reducer[model.to_s] = columns.first
  end
  reducer
end

models_with_files.map do |model_name, file_name|
  model = Object.const_get(model_name)
  model.column_names.each do |column|
    next unless column.include?("#{file_name}_")
    puts "remove_column :#{model.table_name}, :#{column}"
  end
end