Fix 500 error when try to update own profile in admin area

app/controllers/admin/users_controller.rb

@@ -68,7 +68,9 @@ class Admin::UsersController < Admin::ApplicationController
       params[:user].delete(:password_confirmation)
     end
 
-    user.admin = (admin && admin.to_i > 0)
+    if admin.present?
+      user.admin = !admin.to_i.zero?
+    end
 
     respond_to do |format|
       if user.update_attributes(params[:user], as: :admin)

features/admin/users.feature

@@ -14,3 +14,9 @@ Feature: Admin Users
     And Click save
     Then See username error message
     And Not changed form action url
+
+  Scenario: Edit my user attributes
+    Given I visit admin users page
+    And click edit on my user
+    When I submit modified user
+    Then I see user attributes changed

features/steps/admin/admin_users.rb

@@ -31,4 +31,17 @@ class AdminUsers < Spinach::FeatureSteps
   And 'Not changed form action url' do
     page.should have_selector %(form[action="/admin/users/#{@user.username}"])
   end
+
+  step 'I submit modified user' do
+    check :user_can_create_group
+    click_button 'Save'
+  end
+
+  step 'I see user attributes changed' do
+    page.should have_content 'Can create groups: Yes'
+  end
+
+  step 'click edit on my user' do
+    find("#edit_user_#{current_user.id}").click
+  end
 end