Eseguire il comando :
gem install activerecord-sqlserver-adapter
In order to use SQL Server with Rails, you must first install the file, ADO.rb. We supply this file in the Ruby In Steel installation archive. You should copy ADO.rb into the \lib\dbd\ directory beneath your Ruby installation. For example, if Ruby is installed in C:\ruby you would need to copy ADO.rb into: ruby\lib\ruby\site_ruby\1.8\DBD\ADO\. You may need to create the \ADO directory. If you do not use SQL Server, this file is not required.
Il file lo si trova all'indirizzo : http://rubyforge.org/frs/?group_id=234&release_id=38997
il file da scaricare รจ il "ruby-dbi" versione 0.2.2 (le altre versioni non contengono il file ADO).