also watch CSS in unicorn on dev

config/environments/development.rb

@@ -52,7 +52,7 @@ Discourse::Application.configure do
     config.developer_emails = emails.split(",").map(&:downcase).map(&:strip)
   end
 
-  if defined?(Rails::Server) || defined?(Puma)
+  if defined?(Rails::Server) || defined?(Puma) || defined?(Unicorn)
     require 'stylesheet/watcher'
     STDERR.puts "Starting CSS change watcher"
     @watcher = Stylesheet::Watcher.watch

lib/stylesheet/watcher.rb

@@ -68,9 +68,12 @@ module Stylesheet
       Stylesheet::Manager.cache.clear
 
       message = ["desktop", "mobile", "admin"].map do |name|
-        { target: name, new_href: Stylesheet::Manager.stylesheet_href(name.to_sym) , theme_key: SiteSetting.default_theme_key }
+        {
+          target: name,
+          new_href: Stylesheet::Manager.stylesheet_href(name.to_sym),
+          theme_key: SiteSetting.default_theme_key
+        }
       end
-
       MessageBus.publish '/file-change', message
     end