Add constants

lib/planet_express_express.rb

@@ -1,6 +1,8 @@
 # frozen_string_literal: true
 
 require_relative "planet_express_express/version"
+require_relative "planet_express_express/constants"
+
 
 module PlanetExpressExpress
   class Error < StandardError; end

lib/planet_express_express/constants.rb

@@ -0,0 +1,12 @@
+module PlanetExpressExpress
+  PRICE_LIST = {
+    [:LP, :S] => 1_50,
+    [:LP, :M] => 4_90,
+    [:LP, :L] => 6_90,
+    [:MR, :S] => 2_00,
+    [:MR, :M] => 3_00,
+    [:MR, :L] => 4_00,
+  }.freeze
+
+  DISCOUNT_LIMIT = 10_00
+end