[jeremyevans]

That could be the case, but if you are going to open source the application, what would be the point of trying to hide it?

Considering that password hashes are stored in the users table, it seems unlikely. While you can use PostgreSQL to implement per-column permissions, it's a fairly large pain, and you have to make sure every query you are using that selects from the table does not select that column. Rails/ActiveRecord by default selects all columns in the model's table, and it's a fair amount of work to work around that.