Force max length for string in PostgreSQL

I am using heroku for a RoR application and am trying to manually set the length of a string column and am having trouble.

I tried making a migration along the lines of

change_column :posts, :content, :string, :length => 10000

I assumed this would work but no such luck, anyone have some pointers?

Thanks!

The length limit option in Rails migrations is called :limit:

change_column :posts, :content, :string, :limit => 10000

If you are finding yourself changing VARCHAR length limits a lot, you might want to read @depesz's blog post on VARCHAR vs TEXT.