Many to many and sinatra

many to many

require 'sinatra'
require 'datamapper'

  
DataMapper.setup(:default, "sqlite3://#{Dir.pwd}/cal.db")


class Event
  include DataMapper::Resource
  
  property :id,               Serial
  property :title,            String
  property :text,             Text
  property :contact_name,     String
  property :contact_email,    String
  property :location,         String
  property :event_start_time, String
  property :event_end_time,   String
  property :created_at,       DateTime
  property :approved,         Boolean, :default => false
  
  has n, :categories, :through => Resource
  
end

class Category
  include DataMapper::Resource
  
  property :id,               Serial
  property :name,             String
  
  has n, :events, :through => Resource
  
end


DataMapper.auto_upgrade!


get '/new' do
  @page_title = "New Event"
  erb :new
end

post '/create' do
  
  
@event = Event.new(params[:event])
  if @event.save
    redirect "preview/#{@event.id}"
  else
    redirect('/list')
  end
end


get '/preview/:id' do
  @event = Event.get(params[:id])
  if @event
    erb :preview
  else
    redirect('/list')
  end
end



============ new.erb ==============

<h3>Create A New Event</h3>

<form	action="/create" method="post" id="ad" enctype="multipart/form-data">
	<p>
		<label>Title:</label><br />
		<input type="text" name="event[title]" id="title" />	
	</p>
	<p>
		<label>Start Time:</label><br />
		<input type="text" name="event[event_start_time]" id="start-time" />
	</p>
	<p>
		<label>End Time:</label><br />
		<input type="text" name="event[event_end_time]" id="end-time" />
	</p>
	<p>
		<label>Location:</label><br />
		<input type="text" name="event[location]" id="location" />
	</p>
	<p>
		<label>Summary:</label><br />
		<textarea name="event[text]" id="summary"></textarea>
	</p>
  <p>
		<label>Category:</label><br />
		<input type="text" name="category[name]" id="category" />
	</p>
	<p>
		<input type="submit">
	</p>
</form>




============= preview.erb ============


<h1> Preview </h1>
<p>
  <b>Title:</b>
  <%= @event.title %>
</p>
<p>
  <b>Start Time:</b>
  <%= @event.event_start_time %>
</p>
<p>
  <b>End Time:</b>
  <%= @event.event_end_time %>
</p>
<p>
  <b>Location:</b>
  <%= @event.location %>
</p>
<p>
  <b>Summary:</b>
  <%= @event.text %>
</p>
<p>
  <b>Category:</b>
  <%= @event.category_events.count %>

</p>