vim: add snipmate config

vim/plugins_config.vim

@@ -145,3 +145,11 @@ let g:gutentags_file_list_command = {
                                  \ },
                              \ }
 let g:gutentags_ctags_exclude = ['build', 'dist', '*css', '*json', '*yaml', '*md']
+
+"" snipmate
+" Silence deprecation warning
+let g:snipMate = { 'snippet_version' : 1 }
+" show description in snipmate's tab completion
+let g:snipMate.description_in_completion = 1
+
+let g:ackprg = 'rg --vimgrep --no-heading'