See the readme changes for an example. In short, this behaves
like verify_authorized but is useful for actions that find a
collection (like index) and don't authorize instances.
The `BlogPolicy -> "BlogPolicy" -> "Blog" -> "BlogPolicy" -> BlogPolicy`
issue @jnicklas pointed out has been resolved. For example, given
```ruby
class BlogPolicy < Struct.new(:user, :blog); end
class Blog; end
class ArtificialBlog < Blog
def self.policy_class
BlogPolicy
end
end
```
The above string manipulation/casting is prevented; the `BlogPolicy`
class will be immediately returned to `policy` and on to be evaluated.
Anonymous classes are now supported too. For example, given
```ruby
class BlogPolicy < Struct.new(:user, :blog); end
class Blog; end
class ArtificialBlog < Blog
def self.policy_class
Struct.new(:user, :blog) do
def create?
true
end
end
end
end
```
The `Struct` will be returned and evaluated as any other policy.
