Update runtime files.
diff --git a/runtime/ftplugin/groovy.vim b/runtime/ftplugin/groovy.vim
new file mode 100644
index 0000000..cc7d6e3
--- /dev/null
+++ b/runtime/ftplugin/groovy.vim
@@ -0,0 +1,19 @@
+" Vim filetype plugin file
+" Language: groovy
+" Maintainer: Justin M. Keyes <justinkz@gmail.com>
+" Last Change: 2016 May 22
+
+if exists('b:did_ftplugin')
+ finish
+endif
+let b:did_ftplugin = 1
+
+let s:cpo_save = &cpo
+set cpo-=C
+
+let b:undo_ftplugin = 'setlocal commentstring<'
+
+setlocal commentstring=//%s
+
+let &cpo = s:cpo_save
+unlet s:cpo_save