Add github corner (#90)

public/index.html

@@ -49,6 +49,31 @@
     <noscript>
       You need to enable JavaScript to run this app.
     </noscript>
+
+    <!-- https://github.com/tholman/github-corners -->
+      <svg
+        xmlns="http://www.w3.org/2000/svg"
+        width="40"
+        height="40"
+        viewBox="0 0 250 250"
+        style="position: absolute; top: 0; right: 0"
+      >
+        <a href="https://github.com/excalidraw/excalidraw" target="_blank">
+          <path d="M0 0l115 115h15l12 27 108 108V0z" fill="#6c6c6c" />
+          <path
+            class="octo-arm"
+            d="M128 109c-15-9-9-19-9-19 3-7 2-11 2-11-1-7 3-2 3-2 4 5 2 11 2 11-3 10 5 15 9 16"
+            style="transform-origin: 130px 106px"
+            fill="white"
+          />
+          <path
+            class="octo-body"
+            d="M115 115s4 2 5 0l14-14c3-2 6-3 8-3-8-11-15-24 2-41 5-5 10-7 16-7 1-2 3-7 12-11 0 0 5 3 7 16 4 2 8 5 12 9s7 8 9 12c14 3 17 7 17 7-4 8-9 11-11 11 0 6-2 11-7 16-16 16-30 10-41 2 0 3-1 7-5 11l-12 11c-1 1 1 5 1 5z"
+            fill="white"
+          />
+        </a>
+    </svg>
+    </a>
     <div id="root"></div>
     <!--
       This HTML file is a template.