make unsubscribing work even if logged out

app/controllers/notifications_controller.rb

@@ -58,7 +58,8 @@ class NotificationsController < ApplicationController
     # TODO will a logged out user be unsubscribed after logging in?
     # need to use devise stored_url or whatever
     if current_user.nil?
-      return redirect_to sign_in_path, notice: 'Continue to unsubscribe from emails by logging in.'
+      flash[:notice] = 'Continue to unsubscribe from emails by logging in.'
+      return redirect_to "#{sign_in_path}?redirect_to=#{unsubscribe_notifications_path}"
     end
 
     if current_user.emails_allowed == false

app/controllers/users/sessions_controller.rb

@@ -1,4 +1,6 @@
 class Users::SessionsController < Devise::SessionsController
+  after_action :store_location, only: [:new]
+
   protected
 
   def after_sign_in_path_for(resource)
@@ -11,4 +13,12 @@ class Users::SessionsController < Devise::SessionsController
       request.referer || root_path
     end
   end
+
+  private
+
+  def store_location
+    if params[:redirect_to]
+      store_location_for(User, params[:redirect_to])    
+    end
+  end
 end

app/views/layouts/application.html.erb

@@ -64,9 +64,13 @@
             <p id="toast" class="toast">
               <% if devise_error_messages? %>
                 <%= devise_error_messages! %>
-              <% elsif notice %>
+              <% end %>
+              <% if notice %>
                 <%= notice %>
               <% end %>
+              <% if alert %>
+                <%= alert %>
+              <% end %>
             </p>      
             <div id="loading"></div>
         </div>

doc/metamaps-qa-steps.md

@@ -32,6 +32,13 @@ Run these tests to be reasonably sure that your code changes haven't broken anyt
  - Add a number of synapses to one of your maps. Reload to see if they are still there.
  - Rearrange one of your maps and save the layout. Reload to see if the layout is preserved.
 
+### Unsubscribing from Notifications
+
+ - Log out
+ - Visit /notifications/unsubscribe. It should redirect you to the login page.
+ - Log in.
+ - It should redirect you to the user edit page, and you should be unsubscribed.
+
 ### Misc
 
  - Login as admin. Change metacode sets.