Add Advance The Date as a rails til

README.md

@@ -7,7 +7,7 @@ variety of languages and technologies. These are things that don't really
 warrant a full blog post. These are mostly things I learn by pairing with
 smart people at [Hashrocket](http://hashrocket.com/).
 
-_461 TILs and counting..._
+_462 TILs and counting..._
 
 ---
 
@@ -278,6 +278,7 @@ _461 TILs and counting..._
 
 ### Rails
 
+- [Advance The Date](rails/advance-the-date.md)
 - [All or Nothing Database Transactions](rails/all-or-nothing-database-transactions.md)
 - [Attach A File With Capybara](rails/attach-a-file-with-capybara.md)
 - [Attribute Getter without the Recursion](rails/attribute-getter-without-the-recursion.md)

rails/advance-the-date.md

@@ -0,0 +1,17 @@
+# Advance The Date
+
+In Rails land, you can advance a date forward and backward with the
+`#advance` method:
+
+```ruby
+> Date.today
+=> Wed, 31 Aug 2016
+> Date.today.advance(days: 1)
+=> Thu, 01 Sep 2016
+> Date.today.advance(months: 1)
+=> Fri, 30 Sep 2016
+> Date.today.advance(months: -2)
+=> Thu, 30 Jun 2016
+```
+
+h/t Dillon Hafer