<%= form_for [:admin, @user], :remote => true do |f| %>
  <%= error_messages_for(@user) %>
  <label>Name</label><%= f.text_field :name %><br />
  <label>Email</label> <%= f.text_field :email %><br />
  <% if @user.new_record? %>
    <label>Password</label> <%= f.password_field :password %><br />
    <label>Password confirmation</label> <%= f.password_field :password_confirmation %><br />
  <% end %>
  <label>Is manager</label> <%= f.check_box :is_manager %>
<% end %>

<%= form_for [:admin, @user], :remote => true do |f| %>
  <%= error_messages_for(@user) %>
  <label>Name</label><%= f.text_field :name %><br />
  <label>Email</label> <%= f.text_field :email %><br />
  <% if @user.new_record? %>
    <label>Password</label> <%= f.password_field :password %><br />
    <label>Password confirmation</label> <%= f.password_field :password_confirmation %><br />
  <% end %>
  <% if current_user.is_manager? %>
    <label>Is manager</label> <%= f.check_box :is_manager %>
  <% end %>
<% end %>

Hide is_manager controller if user is not a manager
Hide is_manager controller if user is not a manager
