use template for post list

embed/post-list.html

@@ -0,0 +1,3 @@
+{{range .}}
+    <h2><a href="{{.UrlPath}}">{{.Title}}</a></h2>
+{{end}}

renderer.go

@@ -86,9 +86,9 @@ func RenderPost(post Post) (string, error) {
 func RenderIndexPage(user User) (string, error) {
 	posts, _ := user.Posts()
 
-	postHtml := ""
+	postHtml, err := renderEmbedTemplate("embed/post-list.html", posts)
-	for _, post := range posts {
+	if err != nil {
-		postHtml += "<h2><a href=\"" + post.UrlPath() + "\">" + post.Title() + "</a></h2>\n"
+		return "", err
 	}
 
 	data := PageContent{