title: Can't put email address field on login form (Authlogic)
body: <p>So I have Authlogic working fine with this <code>user_sessions/new</code> view:</p>
  
  <pre><code>&lt;% form_for @user_session, :url =&gt; user_session_path do |f| %&gt;
  
    &lt;% if @user_session.errors.present? %&gt;
      Invalid username or password
    &lt;% end %&gt;
  
    &lt;%= f.label :login %&gt;&lt;br /&gt;
    &lt;%= f.text_field :login %&gt;&lt;br /&gt;
    &lt;br /&gt;
    &lt;%= f.label :password %&gt;&lt;br /&gt;
    &lt;%= f.password_field :password %&gt;&lt;br /&gt;
    &lt;br /&gt;
    &lt;%= f.check_box :remember_me, :style =&gt; 'margin-right: 10px' %&gt;
    &lt;%= f.label :remember_me %&gt;&lt;br /&gt;
    &lt;br /&gt;
    &lt;%= f.submit "Login" %&gt;
  &lt;% end %&gt;
  </code></pre>
  
  <p>But when I change</p>
  
  <pre><code>  &lt;%= f.label :login %&gt;&lt;br /&gt;
    &lt;%= f.text_field :login %&gt;&lt;br /&gt;
  </code></pre>
  
  <p>to</p>
  
  <pre><code>  &lt;%= f.label :email %&gt;&lt;br /&gt;
    &lt;%= f.text_field :email %&gt;&lt;br /&gt;
  </code></pre>
  
  <p>I get this error when I load the view:</p>
  
  <pre><code>undefined method `email' for #&lt;UserSession: no credentials provided&gt;
  </code></pre>
  
  <p>But of course my users table has an <code>email</code> field, etc.</p>