gistfile1.txt

class FiltersController < ApplicationController
  def update
    if params[:filter]
      @filter = ::Filter.find params[:id]
      @filter.attributes = params[:filter]
    else
      method = "add_or_remove_#{find_attribut}"
      self.send(method) #if self.respond_to?(method)
      return
    end
    respond_to do |format|
      format.js
    end 
  end 

private
  def find_attribut
    %w(people system project status).detect { |attribut| params[attribut] }
  end
  def add_or_remove_people
    add_or_remove_objekt :people, Person.find(params[:people])
  end

  def add_or_remove_system
    add_or_remove_objekt :system, System.find(params[:system])
  end

  def add_or_remove_objekt attribute, object
    @attribute = attribute
    @object = object
    if @filter.send(@attribute).include?(@object)
      @filter.send(@attribute).delete @object
      render_remove
    else
      @filter.send(@attribute) << @object
      render_add
    end
  end


end

gistfile2.txt