Updates README with lesson ID.
Updates README with lesson ID.

eliz79/is210-week-13-synthesizing,neal-rogers/is210-week-13-synthesizing,is210-2015-fall-01/is210-week-13-synthesizing,is210-2015-fall-02/is210-week-13-synthesizing,is210-2015-fall-02/is210-week-13-synthesizing,is210-faculty/is210-week-13-synthesizing,neal-rogers/is210-week-13-synthesizing,eliz79/is210-week-13-synthesizing,ModestoCabrera/is210-week-13-synthesizing,Logan213/is210-week-13-synthesizing,ModestoCabrera/is210-week-13-synthesizing,is210-2015-fall-01/is210-week-13-synthesizing,Logan213/is210-week-13-synthesizing,is210-faculty/is210-week-13-synthesizing