Adapters not working with datamapper

Question

I have the following code:

require \'sinatra\'
require \'datamapper\'

DataMapper.setup :default, \"postgres://localhost/mydb\"

However, when I

Answer 1

You should use dm-core instead of datamapper in your require line.

Are you using Bundler? Provided you have bundler set up correctly, it should already be loaded for you.

Answer 2

Uninstalling dm-postgres-adapter 1.2.0.rc2 fixed it.