Add reCAPTCHA support to registration.

Because I *hate* spam bots.

app/controllers/registrations_controller.rb

@@ -1,5 +1,5 @@
 class RegistrationsController < Devise::RegistrationsController
-  before_action :configure_permitted_parameters, if: :devise_controller?
+  prepend_before_action :check_captcha, only: [:create]
 
   def edit
     @openids = Openid.where(user_id: current_user.id).order(:provider)
@@ -21,14 +21,35 @@ class RegistrationsController < Devise::RegistrationsController
     edit_user_registration_path(resource)
   end
 
-  def configure_permitted_parameters
-    devise_parameter_sanitizer.permit(:account_update) do |u|
-      u
-          .permit(:email, :password, :password_confirmation, :current_password, :username, :email_public)
-    end
-    devise_parameter_sanitizer.permit(:sign_up) do |u|
-      u
-          .permit(:email, :password, :password_confirmation, :name, :username)
+  private
+
+  def sign_up_params
+    params.require(:user).permit(
+      :email,
+      :password,
+      :password_confirmation,
+      :name,
+      :username
+    )
+  end
+
+  def account_update_params
+    params.require(:user).permit(
+      :email,
+      :password,
+      :password_confirmation,
+      :current_password,
+      :username,
+      :email_public
+    )
+  end
+
+  def check_captcha
+    unless verify_recaptcha
+      self.resource = resource_class.new sign_up_params
+      resource.validate # Look for any other validation errors besides Recaptcha
+      respond_with_navigational(resource) { render :new }
     end
   end
+
 end