README.md in of-0.3.0 vs README.md in of-0.4.0

@@ -35,12 +35,23 @@
   3.of(Object) # => [#<Object:0x007fb0db8b75c0>, #<Object:0x007fb0db8b7548>, #<Object:0x007fb0db8b74f8>]
 end
 ```
 
 ## Usage with Refinements
+
+use the following in the gemfile:
+
 ```ruby
+# Gemfile
+# ...
+gem 'of', require: 'of/refinements'
+```
+
+and then use the refinement:
+
+```ruby
 class MyClass
-  use Of
+  using Of
 
   def 7_of_9
     7.of { 9 } # => [9, 9, 9, 9, 9, 9, 9, 9]
   end