table.table

tr
  th Username
  - @roles.each do |role|
    th = role.to_s.titleize
  end
- @users.each do |user|
  tr
    td = user.username
    - @roles.each do |role|
      td
        = form_for user, url: role_user_path(user), method: :put do |f|
            - operation, activation, btn_class = user.has_role?(role) ? \
              %w(revoke active btn-success) : %w(grant inactive btn-danger)
            = hidden_field_tag :operation, operation
            = hidden_field_tag :role, role
            = f.submit activation, class: "btn #{btn_class}"