Feat(plugin): add link to sources in template

theme/static/stylesheet/style.less

@@ -350,6 +350,33 @@ main {
     padding-top: 1em;
 }
 
+.source {
+    text-align: center;
+    padding-top: 1em;
+    img {
+        border: 0;
+        box-shadow: none;
+    }
+    a {
+        background-color: @tag-bg;
+        padding: .2em .6em .2em;
+        font-size: .74em;
+        line-height: 1;
+        color: @tag-text-color;
+        text-align: center;
+        white-space: nowrap;
+        vertical-align: baseline;
+        border-radius: .25em;
+    }
+
+    a:hover {
+        background-color: @tag-hover-color;
+    }
+
+
+
+}
+
 .tag-cloud {
     text-align: center;
     a {