Replace slug by id

README.adoc

@@ -534,7 +534,7 @@ We update the "blog" Mustache templates.
     {{#articles}}
         <section>
             <header class="article-header">
-                <h2 class="article-title"><a href="/article/{{slug}}">{{title}}</a></h2>
+                <h2 class="article-title"><a href="/article/{{id}}">{{title}}</a></h2>
                 <div class="article-meta">By  <strong>{{author.firstname}}</strong>, on <strong>{{addedAt}}</strong></div>
             </header>
             <div class="article-description">
@@ -591,7 +591,7 @@ class HtmlController(private val repository: ArticleRepository,
     	fun article(@PathVariable id: Long, model: Model): String {
     		val article = repository
     				.findById(id)
-    				.orElseThrow { IllegalArgumentException("Wrong article slug provided") }
+    				.orElseThrow { IllegalArgumentException("Wrong article id provided") }
     				.render()
     		model["title"] = article.title
     		model["article"] = article