Mention that search params key is now configurable

README.md

@@ -35,7 +35,8 @@ If you're coming from MetaSearch, things to note:
   1. The default param key for search params is now `:q`, instead of `:search`. This is
      primarily to shorten query strings, though advanced queries (below) will still
      run afoul of URL length limits in most browsers and require a switch to HTTP 
-     POST requests.
+     POST requests. This key is
+[configurable](https://github.com/ernie/ransack/wiki/Configuration)
   2. `form_for` is now `search_form_for`, and validates that a Ransack::Search object
      is passed to it.
   3. Common ActiveRecord::Relation methods are no longer delegated by the search object.