Update index.html

Fix typos

Author: mikela

app/index.html

@@ -101,8 +101,8 @@ <h2><i class="fa fa-code-fork"></i> <span id="forks">00</span></h2>
             <div class="introduction">
                 <div class="row">
                     <div class="col-md-8 col-md-offset-2">
-                        <h2 class="text-center">How it works?</h2>
-                        <p class="function text-center">"Scala Exercises" brings the popular <a href="http://www.scalakoans.org/">Scala Koans</a> to the web. Offering hundreds of solveable exercises organized into 42 categories covering the basics of the Scala language.</p>
+                        <h2 class="text-center">How it works</h2>
+                        <p class="function text-center">"Scala Exercises" brings the popular <a href="http://www.scalakoans.org/">Scala Koans</a> to the web. Offering hundreds of solvable exercises organized into 42 categories covering the basics of the Scala language.</p>
                     </div>
                 </div>
             </div>