# This can be improved by Ruby Mixins in the long run, but this is the basics overview

class Grouping < ActiveRecord::Base
  # Takes a gender and queries based on it
  scope :gender, -> (gender) { where: ... }
end

class GroupingsController < ApplicationController
  def index
    @groupings = Grouping.all
    filter_params.each do |key, value|
      # In ruby send is the way to call a method, in this case gender method/scope
      @groupings = @groupings.public_send(key, value) if key.present?
    end
  end

  private

  def filter_params
    params.slice(:gender) # One can add more params here
  end
end