title: Rack::Lint::LintError: Status must be >=100 seen as integer
body: <p>I am using the DataMapper gem with Sinatra and followed the tutorial here:
  <a href="http://net.tutsplus.com/tutorials/ruby/ruby-for-newbies-working-with-datamapper/">http://net.tutsplus.com/tutorials/ruby/ruby-for-newbies-working-with-datamapper/</a></p>
  
  <p>I am connecting to the database and migrating as such:</p>
  
  <pre><code>DataMapper.setup :default, "sqlite://#{Dir.pwd}/ex2.db"
  DataMapper.auto_migrate!
  </code></pre>
  
  <p>My data model:</p>
  
  <pre><code>class User
      include DataMapper::Resource
  
      property :id       , Serial
      property :username , String
      property :email    , String
  end
  </code></pre>
  
  <p>I am executing using this command:</p>
  
  <pre><code>rackup config.ru
  </code></pre>
  
  <p>However, when I get to this line:</p>
  
  <pre><code>User.create username: "JoeSchmo", email: "joe@schmo.com"
  </code></pre>
  
  <p>I receive the error:</p>
  
  <pre><code>Rack::Lint::LintError: Status must be &gt;=100 seen as integer
  </code></pre>
  
  <p>Any idea why this is happening?</p>