app/views/sessions/new.html.erb
<% if flash[:alert] %>
<div id="alert">
<p><%= flash[:alert] %></p>
</div>
<% end %>
<%= form_tag do %>
<div>
<label>Username</label>
<%= text_field_tag :username, params[:username] %>
</div>
<div>
<label>Password</label>
<%= password_field_tag :password, params[:password] %>
<%= submit_tag "Log in", :class => "submit" %>
</div>
<% end %>