%= stylesheet_link_tag "bootstrap_and_overrides", :media => "all" %>
<%= f.submit "Sign in", class:"btn btn-lg btn-primary" %>
Or quickly...
<% User.all.each do |user| %> <%= form_for(resource, :as => resource_name, :url => session_path(resource_name)) do |f| %> <%= f.hidden_field :username, :value => user.username%> <%= f.hidden_field :password, :value => 'password' %> <%= f.submit "Sign in as #{user.username}", class:"btn btn-info" %> <% end %> <% end %>
<% end %>