Migrations rake task. Copied example migrations from examples/ to db/…

…migrations/. Temporarily added a config.rb in the migrations directory for setting up the logger and default database.

*	rake db:migrate 				=> runs migrations up
*	DIRECTION=down rake db:migrate 	=> runs migrations down
*	MIGRATION_DIR rake db:migrate 	=> uses a directory different than ./db/migrations/

Rakefile

@@ -42,3 +42,26 @@ Spec::Rake::SpecTask.new(:spec) do |t|
   t.spec_opts << '--options' << 'spec/spec.opts' if File.exists?('spec/spec.opts')
   t.spec_files = Pathname.glob(Pathname.new(__FILE__).dirname + 'spec/**/*_spec.rb')
 end
+
+namespace :db do
+
+  # pass the relative path to the migrations directory by MIGRATION_DIR
+  task :setup_migration_dir do
+    unless defined?(MIGRATION_DIR)
+      migration_dir = ENV["MIGRATION_DIR"] || File.join("db", "migrations")
+      MIGRATION_DIR = File.expand_path(File.join(File.dirname(__FILE__), migration_dir))
+    end
+    FileUtils.mkdir_p MIGRATION_DIR
+  end
+
+  # set DIRECTION to migrate down
+  desc "Run your system's migrations"
+  task :migrate => [:setup_migration_dir] do
+    require File.expand_path(File.join(File.dirname(__FILE__), "lib", "migration_runner.rb"))
+    require File.expand_path(File.join(MIGRATION_DIR, "config.rb"))
+
+    Dir[File.join(MIGRATION_DIR, "*.rb")].each { |file| require file }
+
+    ENV["DIRECTION"] != "down" ? migrate_up! : migrate_down!
+  end
+end

db/migrations/1_create_people_table.rb

@@ -0,0 +1,12 @@
+migration 1, :create_people_table do
+  up do
+    create_table :people do
+      column :id,     Integer, :serial => true
+      column :name,   String, :size => 50
+      column :age,    Integer
+    end
+  end
+  down do
+    drop_table :people
+  end
+end

db/migrations/2_add_dob_to_people.rb

@@ -0,0 +1,13 @@
+migration 2, :add_dob_to_people do
+  up do
+    modify_table :people do
+      add_column :dob, DateTime, :nullable? => true
+    end
+  end
+
+  down do
+    modify_table :people do
+      drop_column :dob
+    end
+  end
+end

db/migrations/config.rb

@@ -0,0 +1,4 @@
+DataMapper::Logger.new(STDOUT, :debug)
+DataMapper.logger.debug( "Starting Migration" )
+
+DataMapper.setup(:default, 'postgres://postgres@localhost/dm_core_test')