FIX: start filesystem watcher when running under rails s

config/environments/development.rb

@@ -49,16 +49,17 @@ Discourse::Application.configure do
   require 'rbtrace'
 
 
-  require 'stylesheet/watcher'
-  if defined? Puma
-    STDERR.puts "Starting CSS change watcher"
-    @watcher = Stylesheet::Watcher.watch
-  end
 
   if emails = GlobalSetting.developer_emails
     config.developer_emails = emails.split(",").map(&:downcase).map(&:strip)
   end
 
+  if defined? Rails::Server || defined? Puma
+    require 'stylesheet/watcher'
+    STDERR.puts "Starting CSS change watcher"
+    @watcher = Stylesheet::Watcher.watch
+  end
+
   config.after_initialize do
     if ENV['BULLET']
       Bullet.enable = true