[Ruby] [ANN] Acts as securable

[Chris Ochs]

This is my first stab at a more comprehensive rbac plugin for rails.  I 
won't be announcing it anywhere else until I get the web admin interface 
for it done, but I wanted to get some early feedback from this group.  
This was also my first time using rspec, so while there is a test suite, 
I'm not sure if it's really done in the right way.

The basic idea behind securable is this:

- Roles have permissions
- A role is associated with a model/class. 
- Users are assigned roles on instances of the class
- Inheritance gives a user the permissions associated with the role 
assignement, or any child instance that has the same role.

There are some basic docs in the README, and a generator that will 
create the models and migrations.

Any comments appreciated!

http://www.ochsnet.com/svn/acts_as_securable

Chris Ochs