Try to guess application's directory while trying to run the server, but only...

Try to guess application's directory while trying to run the server, but only if config.ru is not present in current dir

railties/lib/rails/commands.rb

@@ -33,8 +33,13 @@
   Rails::Console.start(Rails.application)
 
 when 'server'
+  # try to guess application's path if there is no config.ru file in current dir
+  # it allows to run script/rails server from other directories
+  Dir.chdir(File.expand_path('../../', APP_PATH)) unless File.exists?(File.expand_path("config.ru"))
+
   require 'rails/commands/server'
   Rails::Server.new.tap { |server|
+    # we need to require application after the server sets environment
     require APP_PATH
     Dir.chdir(Rails.application.root)
     server.start