FEATURE: logging out logs you out everywhere

can be disabled by changing the setting "log_out_strict" to false

lib/auth/default_current_user_provider.rb

@@ -82,6 +82,11 @@ class Auth::DefaultCurrentUserProvider
   end
 
   def log_off_user(session, cookies)
+    if SiteSetting.log_out_strict && (user = current_user)
+      user.auth_token = nil
+      user.save!
+      MessageBus.publish "/logout", user.id, user_ids: [user.id]
+    end
     cookies[TOKEN_COOKIE] = nil
   end