Rails Single Table Inheritance

gistfile1.rb

# model finance.rb
class Finance < ActiveRecord::Base
  
  attr_accessible :amount, :date, :description, :type

  belongs_to :users, :dependent => :destroy

end

# model income.rb

class Income < Finance; end

# model expense.rb

class Expense < Finance; end

# controller finances_controller.rb

class FinancesController < ApplicationController
  before_filter :authenticate_user!

  def index
    @finances = current_user.finances.all
  end

  def new
    @finance = Finance.new
  end

  def create
    @finance = Finance.new(params[:finance])
    @finance.user_id = current_user
    @finance.type = params[:finance_type]
    if @finance.save
      redirect_to finances_path notice: 'Item created.'
    else
      render action: "new"
    end
  end
end

# view entry form _form.html.erb

<%= form_for @finance do |f| %>
  <% if @finance.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(@finance.errors.count, "error") %> prohibited this from being saved:</h2>

      <ul>
      <% @finance.errors.full_messages.each do |msg| %>
        <li><%= msg %></li>
      <% end %>
      </ul>
    </div>
  <% end %>

  
  <%= select_tag(:finance_type, options_for_select([['Income', 'Income'], ['Expense', 'Expense']])) %>
  <div class="field">
    <%= f.label :description %><br />
    <%= f.text_field :description %>
  </div>
  <div class="field">
    <%= f.label :amount %><br />
    <%= f.text_field :amount %>
  </div>
  <div class="field">
    <%= f.label :date %><br />
    <%= date_select :finance, :date %>
  </div>
  <div class="actions">
    <%= f.submit %>
  </div>
<% end %>

# routes.rb

PhotogDesign::Application.routes.draw do
  devise_for :users, path_names: {sign_in: "login", sign_out: "logout"}

  resources :clients

  resources :finances

  resources :income, :controller => 'finances'
end