[Ruby][ActiveRecord] autocompleter suggestions based on attributes with tags (comma separated)

suggestions_for_field.rb

# lib/modules/suggestions_for_field.rb
module SuggestionsByField
  def self.included(base)
    base.extend(ClassMethods)
  end

  module ClassMethods
    def suggestions_for_field(field, query)
      connection.execute("
      select val from (
        select distinct unnest(string_to_array(#{table_name}.#{field}, ',')) as val
        from #{table_name}
      ) sub where sub.val ilike '#{ERB::Util.html_escape(query)}%' limit 10
    ").map(&:values).flatten.sort
    end
  end
end

ActiveRecord::Base.send(:include, SuggestionsByField)

suggestions_for_fields.rb

# config/initializers/suggestions_for_field.rb
require "modules/suggestions_for_field"