new.html.erb

<%= bootstrap_form_for(resource, 
                       :as => resource_name, 
                       :url => registration_path(resource_name)) do |f| %>

  <%= f.text_field :name, 
	           placeholder: 'username (will be shown publicly)', 
	           class: 'form-control' %>
  <%= f.text_field :email, 
	           placeholder: 'email', 
	           class: 'form-control' %>
  <%= f.password_field :password, 
                       placeholder: 'password', 
                       class: 'form-control' %>
  <%= f.password_field :password_confirmation, 
                       placeholder: 'password confirmation', 
                       class: 'form-control' %>
  <%= f.submit 'Sign up', class: 'btn sign-up-button' %>
<% end %>