Make scaffold/migrate/server separate steps.

Many students at the intermediate railsbridge were accidentally pasting the three lines as one and ending up with a very strange migration. I've made these separate so that it is more clear that it is 3 distinct steps.

Author: jesseplusplus

sites/installfest/create_and_deploy_a_rails_app.step

@@ -74,7 +74,11 @@ step "Generate a database model" do
 
   console <<-BASH
 rails generate scaffold user name:string email:string address:text active:boolean
+  BASH
+  console <<-BASH
 rake db:migrate
+  BASH
+  console <<-BASH
 rails server
   BASH