gistfile1.rb

require 'rubygems'
require 'sinatra'
require 'datamapper'
DataMapper.setup(:default, 'sqlite3::memory:')

class Idea
  include DataMapper::Resource
  property :id,         Serial
  property :body,       Text
end

DataMapper.auto_migrate!

get '/' do
  "<p>" +
    Idea.count.to_s + 
    Idea.all.inject(""){|sum, idea| sum << "#{idea.body} <br/>" } +
    "</p>" +
    '<form action="/" method="POST">
    <textarea name="idea" id="idea" rows="20"></textarea>
    <br/><input type="submit" value="Submit"/>
    </form>'
end

post '/' do
  idea = Idea.new
  idea.body = params["idea"]
  idea.save
  redirect '/'
end