add contribution link on doc pages

Author: Evan You

themes/vue/layout/page.ejs

@@ -4,4 +4,5 @@
 <div class="content <%- page.type ? page.type + ' with-sidebar' : '' %>">
     <h1><%- page.title %><%- page.type === 'examples' ? ' Example' : '' %></h1>
     <%- page.content %>
+    <div class="footer">Caught a mistake or want to contribute to the documentation? <a href="https://github.com/vuejs/vuejs.org" target="_blank">Fork this site on Github</a>!</div>
 </div>

themes/vue/source/css/page.styl

@@ -136,6 +136,14 @@ $header-height = 40px
             font-weight bold
             font-family Georgia
 
+.footer
+    color $light
+    margin-top 4em
+    padding-top 2em
+    border-top 1px solid #e5e5e5
+    margin-left .8em
+    font-size .9em
+
 @media screen and (min-width: 720px)
     #main.fix-sidebar
         .sidebar
@@ -196,4 +204,7 @@ $header-height = 40px
         &.with-sidebar
             margin-left 0
         figure, p, ul, p.tip
-            margin-left 0
+            margin-left 0
+    .footer
+        margin-left 0
+        text-align center