1 files changed, 12 insertions, 6 deletions
diff --git a/guides/source/migrations.md b/guides/source/migrations.md
index 6100fc89c8..1c858069f3 100644
--- a/guides/source/migrations.md
+++ b/guides/source/migrations.md
@@ -301,11 +301,12 @@ braces. You can use the following modifiers:
 * `precision`    Defines the precision for the `decimal` fields
 * `scale`        Defines the scale for the `decimal` fields
 * `polymorphic`  Adds a `type` column for `belongs_to` associations
+* `null`         Allows or disallows `NULL` values in the column.
 
 For instance, running
 
 ```bash
-$ rails generate migration AddDetailsToProducts price:decimal{5,2} supplier:references{polymorphic}
+$ rails generate migration AddDetailsToProducts 'price:decimal{5,2}' supplier:references{polymorphic}
 ```
 
 will produce a migration that looks like this
@@ -692,15 +693,20 @@ Neither of these Rake tasks do anything you could not do with `db:migrate`. They
 are simply more convenient, since you do not need to explicitly specify the
 version to migrate to.
 
+### Setup the Database
+
+The `rake db:setup` task will create the database, load the schema and initialize
+it with the seed data.
+
 ### Resetting the Database
 
-The `rake db:reset` task will drop the database, recreate it and load the
-current schema into it.
+The `rake db:reset` task will drop the database and set it up again. This is
+functionally equivalent to `rake db:drop db:setup`.
 
 NOTE: This is not the same as running all the migrations. It will only use the
-contents of the current schema.rb file. If a migration can't be rolled back,
-'rake db:reset' may not help you. To find out more about dumping the schema see
-'[schema dumping and you](#schema-dumping-and-you).'
+contents of the current `schema.rb` file. If a migration can't be rolled back,
+`rake db:reset` may not help you. To find out more about dumping the schema see
+[Schema Dumping and You](#schema-dumping-and-you) section.
 
 ### Running Specific Migrations