tap/app/views/devise/sessions/new.html.erb

<h2>Sign in</h2>
<div class="sign-in">
  <%= form_for(resource, :as => resource_name, :url => session_path(resource_name)) do |f| %>

    <%= form_text_field f, :nickname %>
    <%= form_password_field f, :password %>

    <% if devise_mapping.rememberable? %>
      <%= form_check_box f, :remember_me %>
    <% end %>

    <%= f.submit "Sign in", class: "btn btn-primary" %>
  <% end %>
</div>


<%= render "devise/shared/links" %>