bracket.rb

class Bracket < ActiveRecord::Base
  has_one :ownership, :as => :app
  has_one :owner, :through => :ownership, :source => :user

  has_many :memberships, :as => :app, :conditions => "status = '#{Membership::Status::MEMBER}' OR type = 'Ownership'"
  has_many :members, :through => :memberships, :source => :user
end

controller.rb

  def index
    @search = @klass.search(params[:search])
    @records = @search.paginate :per_page => params[:per_page] || 20, :page => params[:page] || 1
  end

form.haml

- form_for @search, :html => {:id => 'bracket_search_form' }do |f|
  = hidden_field_tag :format, 'admin'

  = f.label :owner_email_like, 'Owner Email:'
  = f.text_field :owner_email_like

membership.rb

class Membership < ActiveRecord::Base  
  belongs_to :user
  belongs_to :app, :polymorphic => true
end

ownership.rb

class Ownership < Membership

end

query.sql

SELECT `brackets`.* FROM `brackets` 
	INNER JOIN `memberships` ON (`brackets`.`id` = `memberships`.`app_id` AND `memberships`.`app_type` = 'Bracket') 
	INNER JOIN `users` ON (`users`.`id` = `memberships`.`user_id`) 
	WHERE (users.email LIKE '%dj%') LIMIT 0, 20