module Ransack::Configuration

def add_predicate(name, opts = {})
  name = name.to_s
  opts[:name] = name
  compounds = opts.delete(:compounds)
  compounds = true if compounds.nil?
  compounds = false if opts[:wants_array]
  self.predicates[name] = Predicate.new(opts)
  Constants::SUFFIXES.each do |suffix|
    compound_name = name + suffix
    self.predicates[compound_name] = Predicate.new(
      opts.merge(
        name: compound_name,
        arel_predicate: arel_predicate_with_suffix(
          opts[:arel_predicate], suffix
          ),
        compound: true
      )
    )
  end if compounds
end