fuel.rb in earth-0.11.8

- old
+ new

@@ -1,5 +1,3 @@
-require 'earth/fuel/fuel'
-require 'earth/fuel/fuel_price'
-require 'earth/fuel/fuel_type'
-require 'earth/fuel/fuel_year'
-require 'earth/fuel/greenhouse_gas'
+# lib/earth/fuel.rb
+require 'earth'
+Earth.require_related __FILE__