jobs.rb

# jobs_controller
class JobsController < ApplicationController
  def new
    @job = Job.new
  end
  
  def create
    @job = Job.new(params[:job])
    @job.current_step = session[:listing_step]
    
    if params[:back_button]
      @job.previous_step
    else
      @job.next_step
    end
    
    session[:listing_step] = @job.current_step
    render :action => 'new'
  end
end

#job model
class Job < ActiveRecord::Base
  attr_accessor :title, :description
  attr_writer :current_step

  def current_step
    @current_step || steps.first
  end
  
  def next_step
    self.current_step = steps[steps.index(current_step) + 1]
  end
  
  def previous_step
    self.current_step = steps[steps.index(current_step) - 1]
  end
  
  def steps
    %w[listing_details company_details preview_listing finish]
  end
end