Added a GitHub button in the app bar linking to the repo

Author: magjac

src/ButtonAppBar.js

@@ -12,6 +12,7 @@ import ZoomOutIcon from '@material-ui/icons/ZoomOut';
 import ZoomOutMapIcon from '@material-ui/icons/ZoomOutMap';
 import SettingsIcon from '@material-ui/icons/Settings';
 import HelpIcon from '@material-ui/icons/Help';
+import GitHubIcon from './GitHubIcon'
 
 const styles = {
   root: {
@@ -24,6 +25,12 @@ const styles = {
     marginLeft: -12,
     marginRight: 20,
   },
+  gitHubLink: {
+    color: 'inherit',
+    '&:visited' : {
+      color: 'inherit',
+    },
+  },
 };
 
 function ButtonAppBar(props) {
@@ -145,6 +152,22 @@ function ButtonAppBar(props) {
           >
             <SettingsIcon />
           </IconButton>
+          <a
+            className={classes.gitHubLink}
+            href="https://github.com/magjac/graphviz-visual-editor"
+            target="_blank"
+            rel="noreferrer noopener"
+          >
+            <IconButton
+              color="inherit"
+              aria-label="GitHub"
+            >
+              <GitHubIcon
+                fontSize='inherit'
+                viewBox='-2.4 -2.4 28.8 28.8'
+              />
+            </IconButton>
+          </a>
           <IconButton
             color="inherit"
             aria-label="Help"

src/GitHubIcon.js

@@ -0,0 +1,12 @@
+import React from 'react';
+import SvgIcon from '@material-ui/core/SvgIcon';
+
+function GitHubIcon(props) {
+  return (
+    <SvgIcon {...props}>
+      <path d="M12.007 0C6.12 0 1.1 4.27.157 10.08c-.944 5.813 2.468 11.45 8.054 13.312.19.064.397.033.555-.084.16-.117.25-.304.244-.5v-2.042c-3.33.735-4.037-1.56-4.037-1.56-.22-.726-.694-1.35-1.334-1.756-1.096-.75.074-.735.074-.735.773.103 1.454.557 1.846 1.23.694 1.21 2.23 1.638 3.45.96.056-.61.327-1.178.766-1.605-2.67-.3-5.462-1.335-5.462-6.002-.02-1.193.42-2.35 1.23-3.226-.327-1.015-.27-2.116.166-3.09 0 0 1.006-.33 3.3 1.23 1.966-.538 4.04-.538 6.003 0 2.295-1.5 3.3-1.23 3.3-1.23.445 1.006.49 2.144.12 3.18.81.877 1.25 2.033 1.23 3.226 0 4.607-2.805 5.627-5.476 5.927.578.583.88 1.386.825 2.206v3.29c-.005.2.092.393.26.507.164.115.377.14.565.063 5.568-1.88 8.956-7.514 8.007-13.313C22.892 4.267 17.884.007 12.008 0z" />
+    </SvgIcon>
+  );
+}
+
+export default GitHubIcon;