Add Wipe A Heroku Postgres Database as a devops til.

README.md

@@ -19,6 +19,7 @@ smart people at [Hashrocket](http://hashrocket.com/).
 ### devops
 
 - [Push Non-master Branch To Heroku](devops/push-non-master-branch-to-heroku.md)
+- [Wipe A Heroku Postgres Database](devops/wipe-a-heroku-postgres-database.md)
 
 ### git
 

devops/wipe-a-heroku-postgres-database.md

@@ -0,0 +1,18 @@
+# Wipe A Heroku Postgres Database
+
+If you have some sort of non-production version of an application running on
+Heroku, you may encounter a time when you need to wipe your database and
+start fresh. For a rails project, it may be tempting to do `heroku run rake
+db:drop db:setup`. Heroku doesn't want you to accidentally do anything
+stupid, so it prevents you from running `rake db:drop`. Instead, you must
+send a more explicit command
+
+```
+$ heroku pg:reset DATABASE_URL
+```
+
+Heroku will ask you to confirm that you indeed want to wipe out the database
+and will then proceed.
+
+For the curious reader, running `heroku config` will list the values of a
+number of variables including `DATABASE_URL`.