content updates

doc_collections.md

@@ -1,10 +1,9 @@
 ---
 title:  Collections
-tags: []
-keywords: 
-audience: 
-last_updated: 
-summary: 
+tags: [content-types]
+keywords: groups, api, structure
+last_updated: August 12, 2015
+summary: "Collections are useful if you want to loop through a special folder of pages that you make available in a content API. You could also use collections if you have a set of articles that you want to treat differently from the other content, with a different layout or format."
 ---
 {% include linkrefs.html %}