Added tip

Author: jcxldn

index.html

@@ -12,7 +12,7 @@
         <canvas id="gameCanvas"></canvas>
         </div>
         <div id="info">
-            <p>The invaders get faster and drop more bombs as you complete each level! | Controls: WASD / Arrow Keys + Space</p>
+            <p>The invaders get faster and drop more bombs as you complete each level! | Controls: WASD / Arrow Keys + Space / Touch</p>
             <p><a id="muteLink" href="#" onclick="toggleMute()">Mute</a> | 
                 <a href="https://github.com/dwmkerr/spaceinvaders">Original Project</a> | 
                 <a href="https://github.com/CLSB-Programming/spaceinvaders">GitHub Project</a> |