app/views/mtdevise/account/sessions/new.html.erb
<%= link_to "New User?", mtdevise.user_sign_up_url %>
<h2>Sign In</h2>
<%= form_for @user, :url => sessions_url do, html: {class: 'form-vertical multiple_tags', role: 'form'} |f| %>
<%= render 'shared/validation', object: f.object %>
<p>
<%= f.label :email %><br>
<%= f.email_field :email%>
</p>
<p>
<%= f.label :password %><br>
<%= f.password_field :password%>
</p>
<p>
<%= f.submit "Sign In", :class => "btn btn-primary" %>
</p>
<% end %>