added link to github in the corner

index.html

···
     </form>
   </div>
 
+  <div id="github">
+    <a href="https://github.com/mackuba/skythread" target="_blank">
+      <img src="icons/github.png">
+    </a>
+  </div>
+
   <div id="login">
     <form method="get">
       <h2>🌤 Skythread</h2>

style.css

···
   color: rgb(0, 0, 255);
 }
 
+#github {
+  position: fixed;
+  bottom: 10px;
+  right: 10px;
+}
+
+#github img {
+  width: 20px;
+  opacity: 0.4;
+}
+
+#github a:hover img {
+  opacity: 0.6;
+}
+
 #search {
   visibility: hidden;
   position: fixed;