From f45379e387903d369ad8a1c7b2d1e0aee0ad68ba Mon Sep 17 00:00:00 2001
From: jbranchaud <jbranchaud@gmail.com>
Date: Fri, 1 Jan 2016 12:26:45 -0600
Subject: [PATCH] Add Migrating Up Down Up as a rails til.

---
 README.md                     |  1 +
 rails/migrating-up-down-up.md | 16 ++++++++++++++++
 2 files changed, 17 insertions(+)
 create mode 100644 rails/migrating-up-down-up.md

diff --git a/README.md b/README.md
index 0364c88..be59a84 100644
--- a/README.md
+++ b/README.md
@@ -175,6 +175,7 @@ smart people at [Hashrocket](http://hashrocket.com/).
 - [Creating Records of Has_One Associations](rails/creating-records-of-has-one-associations.md)
 - [Hash Slicing](rails/hash-slicing.md)
 - [Ignore Poltergeist JavaScript Errors](rails/ignore-poltergeist-javascript-errors.md)
+- [Migrating Up Down Up](rails/migrating-up-down-up.md)
 - [Params Includes Submission Button Info](rails/params-includes-submission-button-info.md)
 - [Pretend Generations](rails/pretend-generations.md)
 - [Retrieve An Object If It Exists](rails/retrieve-an-object-if-it-exists.md)
diff --git a/rails/migrating-up-down-up.md b/rails/migrating-up-down-up.md
new file mode 100644
index 0000000..76a72e2
--- /dev/null
+++ b/rails/migrating-up-down-up.md
@@ -0,0 +1,16 @@
+# Migrating Up Down Up
+
+When writing Rails migrations, it is good to define, when possible, what
+should happen when migrating *up* and what should happen when migrating
+*down*. You'll then want to check that both the *up* and *down* work. This
+can be accomplished using the following one-liner:
+
+```bash
+$ rake db:migration && rake db:migration:redo
+```
+
+The `rake db:migration` does what we would expect applying our new migration
+and showing us that our *up* works. The `rake db:migrate:redo` first
+performs a rollback, showing us that our *down* works, and then migrates
+back up again. We now know that our latest migration works going both
+directions.