Hook enroll back up.

lms/templates/portal/course_about.html

@@ -22,7 +22,7 @@
       </section>
       <section class="actions">
         <div class="register-wrapper">
-          <a href="#" class="register">Register</a>
+          <a href="${reverse('enroll', args=[course.id])}" class="register">Register</a>
         </div>
         <section class="social-sharing">
           <p><span class="num-people-registered">1,435</span> students already registed!</p>