Merge pull request rails#11370 from dpdawson/master

Fix a grammatical error/typo in Active Record Migrations guide. [ci skip]

Author: rafaelfranca

guides/source/migrations.md

@@ -376,7 +376,7 @@ create_join_table :products, :categories, column_options: {null: true}
 will create the `product_id` and `category_id` with the `:null` option as
 `true`.
 
-You can pass the option `:table_name` with you want to customize the table
+You can pass the option `:table_name` when you want to customize the table
 name. For example,
 
 ```ruby