Merge pull request jonleighton#13 from trliner/master

Update README.md - add instructions for generating a springified binstub

Author: jonleighton

README.md

@@ -10,3 +10,6 @@ Add to your Gemfile:
 ``` ruby
 gem "spring-commands-rspec", group: :development
 ```
+
+If you're using spring binstubs, run `bundle exec spring binstub rspec` to generate `bin/rspec`.
+Then run `spring stop` to pick up the changes.