Rails 3 DataMapper dm-rails sqlite3 issue

I've tried to take a look to DataMapper with Rails 3, so I follow this
simple instruction on http://github.com/datamapper/dm-rails.

$ rails new testing_dm3 -m http://datamapper.org/templates/rails.rb
$ cd testing_dm3
$ bundle install
$ rails g scaffold Person name:string
$ rake db:setup
Use RbConfig instead of obsolete and deprecated Config.
(in /Users/jm/dev/personal/testing_dm3)
[datamapper] Created database 'testing_dm3_development.db'
[datamapper] Created database 'testing_dm3_test.db'
[datamapper] Finished auto_migrate! for :default repository

$ thin start (I like thin)

Go to and you should see

DataObjects::SyntaxError in People#index
no such table: people

If you don't, you are lucky. I fixed this modifying database.yml:

change "database" to "path"
   database: testing_dm3_development.db
    path: ./db/testing_dm3_development.db

and run:

$ rake db:setup (again)

That fixed it for me. That happend because the database is in_memory and
doesn't create the files, if you run the migration on a rails console,
inside the console you can CRUD your objects, but when you left the
session you lost the data.