cd ~/lib
svn co http://datamapper.rubyforge.org/svn/trunk/ data_mapper
cd data_mapper
rake gem
gem install -l pkg/datamapper-0.2.3.gem
gem install merb_datamapper
sudo bash -c "ARCHFLAGS='-arch i386' gem install do_sqlite3"  # install DataObjects for Sqlite3
cd $MY_MERB_APP
# shutdown any running Merb app servers
# uncomment `use_orm :datamapper` in `config/dependencies.rb`
rake   # this will create the sample database.yml config file
# open `config/database.sample.yml` and edit it to my needs (adapter: sqlite3 and database: dev/app_dev)
mv config/database.sample.yml config/database.yml
# create your empty databases by hand (the ones referenced by database.yml)
sqlite3 db/appname_dev; sqlite3 db/appname_test; sqlite3 db/appname_prod
# change your model to derive from DataMapper::Base and map it to some db fields:
  property :name, :string
  property :created_at, :datetime
merb -i
irb_prompt>> DataMapper::Base.auto_migrate!
irb_prompt>> MyModel.create(:name => "Chabone!")
irb_prompt>> exit
merb   # start up the server