README.md in si-0.1.2 vs README.md in si-0.1.3

@@ -21,9 +21,11 @@
 ### `si`
 
 Express a numeric value with SI prefix.
 
 ```ruby
+require 'si'
+
 0.9.si            # '900m'
 9.si              # '9'
 98.si             # '98'
 987.si            # '987'
 9876.si           # '9.88k'