Use Rails default banner.

railties/lib/generator/base.rb

@@ -26,6 +26,14 @@ module Rails
         end
       end
 
+    protected
+
+      # Use Rails default banner.
+      #
+      def self.banner
+        "#{$0} #{self.arguments.map{ |a| a.usage }.join(' ')} [options]"
+      end
+
       # Small macro to ruby as an option to the generator with proper default
       # value plus an instance helper method.
       #

railties/lib/generator/generators/app.rb

@@ -7,7 +7,7 @@ module Rails::Generators
   class App < Base
     DATABASES = %w( mysql oracle postgresql sqlite2 sqlite3 frontbase ibm_db )
 
-    namespace :rails
+    namespace "rails:app"
     add_shebang_option!
 
     argument :app_path, :type => :string