Update folder references in guide (#237)

Author: frankieroberto

app/guide/how-to-publish.md

@@ -21,8 +21,8 @@ You need three things to contribute:
 ## How to publish a post
 
 1. Create a branch. The name of the branch doesn’t matter too much but you could name it after your post title.
-2. Add a new markdown file in `app/posts/[service-name]/YYYY/MM/[post-name].md`. It’s often easier to duplicate an existing post. That way, you will have the headers that contain basic information that all posts need.
+2. Add a new markdown file in `app/[service-name]/YYYY/MM/[post-name]/index.md`. It’s often easier to duplicate an existing post. That way, you will have the headers that contain basic information that all posts need.
 3. Edit the post with your content – make sure it has a title and date.
-4. If you have images, add them to a folder in `app/images/[service-name]/YYYY/MM/[post-name]/`.
+4. If you have images or PDFs, add them to the same subfolder containing the post, for example `app/[service-name]/YYYY/MM/[post-name]/`.
 5. Open a pull request with your changes and ask for someone to review it. A preview will be available linked from the pull request.
 6. Once it’s reviewed, you can merge the pull request and the post will appear live within a minute or so.