added rake db:create that executes mysql:build_databases and postgresql:build_databases

activerecord/Rakefile

@@ -39,6 +39,15 @@ namespace :test do
   end
 end
 
+namespace :db do
+  task :create do
+    puts "*** creating mysql databases now ***"
+    Rake::Task['mysql:build_databases'].execute
+    puts "*** creating postgresql databases now ***"
+    Rake::Task['postgresql:build_databases'].execute
+  end
+end
+
 %w( mysql mysql2 postgresql sqlite3 sqlite3_mem firebird db2 oracle sybase openbase frontbase jdbcmysql jdbcpostgresql jdbcsqlite3 jdbcderby jdbch2 jdbchsqldb ).each do |adapter|
   Rake::TestTask.new("test_#{adapter}") { |t|
     adapter_short = adapter == 'db2' ? adapter : adapter[/^[a-z0-9]+/]