Session tokens ought not be null

Author: dhh

railties/lib/rails/generators/rails/authentication/authentication_generator.rb

@@ -35,7 +35,7 @@ def enable_bcrypt
 
       def add_migrations
         generate "migration CreateUsers email_address:string!:uniq password_digest:string! --force"
-        generate "migration CreateSessions user:references token:token ip_address:string user_agent:string --force"
+        generate "migration CreateSessions user:references token:token! ip_address:string user_agent:string --force"
       end
     end
   end