## Overview
Once someone finds a conversation (blog post) they'd like to join, let them read the blog post, read the conversation that's happened so far, and then respond below it.
## Implementation
Besides the design (see below), the biggest part of this is the reply area. It should work similarly to the Write.as editor:
* Auto-save the text locally
* Support Markdown
Instead of a single "Post" action, present a choice:
1. Reply here
2. Convert to a draft blog post (go to Write.as)
3. Send privately (via email right now)
In this task, we'll only address #1.
Store the reply in the `posts` table, `content_type = reply`. Then create a new `replies` table:
| post_id | in_reply_to |
(Consider future attributes: muted, featured, etc.)
### Design
Show a link to the original blog post prominently at the top (aggregator site-style), and the conversation below.