In app_generator fix hardcoded bundle call to derive the bundle executable name from ruby_install_name.

This ensures that eg. when `rails` is called from `ruby1.9`, `bundle1.9` is called.

Calling just `bundle` would use the ruby 1.8 bundle.

Author: kch

railties/lib/generators/rails/app/app_generator.rb

@@ -175,7 +175,9 @@ def apply_rails_template
     end
 
     def bundle_if_dev_or_edge
-      run "bundle install" if dev_or_edge?
+      require 'rbconfig'
+      bundle_bin = RbConfig::CONFIG['ruby_install_name'].sub('ruby', 'bundle')
+      run "#{bundle_bin} install" if dev_or_edge?
     end
 
     protected