Start on articles

app/models/article.rb

+class Article < Post
+  default_scope { where(post_type_id: Article.post_type_id) }
+
+  def self.post_type_id
+    PostType.mapping['Article']
+  end
+end
\ No newline at end of file

db/seeds/post_types.yml

@@ -2,3 +2,4 @@
 - name: Answer
 - name: PolicyDoc
 - name: HelpDoc
+- name: Article
\ No newline at end of file