Add link to source code

src/images/ic_code_18px.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" width="18" height="18" viewBox="0 0 24 24"><path fill="none" d="M0 0h24v24H0V0z"/><path d="M9.4 16.6L4.8 12l4.6-4.6L8 6l-6 6 6 6 1.4-1.4zm5.2 0l4.6-4.6-4.6-4.6L16 6l6 6-6 6-1.4-1.4z"/></svg>

src/popup.html

@@ -166,6 +166,10 @@
         <md-icon md-svg-src="images/ic_attach_money_18px.svg"></md-icon>
         <p>Donate</p>
       </md-list-item>
+      <md-list-item ng-click="openLink('https://github.com/hao1300/modheader')">
+        <md-icon md-svg-src="images/ic_code_18px.svg"></md-icon>
+        <p>Source code</p>
+      </md-list-item>
       <md-list-item ng-click="openLink('https://mod-header.appspot.com/help.html')">
         <md-icon md-svg-src="images/ic_help_24px.svg"></md-icon>
         <p>Help</p>