Fix typo

README.md

@@ -18,7 +18,7 @@ If the selector is a directory, `gosher` will look for a file named
 `gophermap` to render the submenu. If a `gophermap` does not exist,
 `gosher` looks for the index.gph gopherfile in the folder and, if it
 exists, renders it as a gophermap. If the required selector has a '.gph'
-extension, `gosher` will treat it as a gopherpile, and render it as a
+extension, `gosher` will treat it as a gopherfile, and render it as a
 gophermap.