Use PostgreSQL enum as rails enum

application_record.rb

# Add the `native_enum` class method to your ApplicationRecord, like this,
# You can then use it in your model, and use postgres enum just like rails enum
#
# Eample:
# class Post < ApplicationRecord
#   native_enum :status
# end
#
# Post.published.count => 0
class ApplicationRecord < ActiveRecord::Base
  class << self
    # Maps a pg enum column as rails enum
    def native_enum(attribute)
      column = column_for_attribute(attribute)
      query = "SELECT enum_range(NULL::#{column.sql_type})"
      values = PG::TextDecoder::Array.new.decode(connection.execute(query).values[0][0])

      enum attribute.to_sym => Hash[values.zip(values)]
    end
  end
end