Gem version changes shouldn't be happening on the fly, so cache these…

… values to avoid lots of unnecessary string comparisons

lib/goldiloader/compatibility.rb

@@ -4,15 +4,15 @@ module Goldiloader
   module Compatibility
 
     def self.mass_assignment_security_enabled?
-      ::ActiveRecord::VERSION::MAJOR < 4 || defined?(::ActiveRecord::MassAssignmentSecurity)
+      @mass_assignment_security_enabled ||= (::ActiveRecord::VERSION::MAJOR < 4 || defined?(::ActiveRecord::MassAssignmentSecurity))
     end
 
     def self.association_finder_sql_enabled?
-      ::Gem::Version.new(::ActiveRecord::VERSION::STRING) < ::Gem::Version.new('4.1')
+      @association_finder_sql ||= (::Gem::Version.new(::ActiveRecord::VERSION::STRING) < ::Gem::Version.new('4.1'))
     end
 
     def self.unscope_query_method_enabled?
-      ::Gem::Version.new(::ActiveRecord::VERSION::STRING) >= ::Gem::Version.new('4.1')
+      @unscope_query_method ||= ::Gem::Version.new(::ActiveRecord::VERSION::STRING) >= ::Gem::Version.new('4.1')
     end
   end
 end