I thought I'd try using clearance to handle authentication on the Rails app I'm developing. It seems pretty nice and basic, but I wanted to add a :name property on the user model (not for authentication, just for display purposes). Once I'd created a migration to add the new column to the user model, I needed to add the field on the corresponding view so it could actually be input by a user. Since clearance is installed as a vendor gem/engine (still not sure what the difference is) the view files are located in the vendor directory. I figured updating these files wouldn't be good, since they'd be overwritten if I ever had to update and unpack the gem.
It turns out all I had to do was copy the view files into my app under the views/user/ directory. I could then modify the files at will, and they would be used by Rails instead of the vendor files. One other gotcha was to make sure to add the attr_accessible :name declaration in my user.rb file (so Rails can do a mass assignment of the posted form items). My user.rb ended up looking like this:
class User < ActiveRecord::Base include Clearance::User has_many :properties attr_accessible :name end