Add option to specify a different config file; update README and CHANGELOG

CHANGELOG.md

@@ -1,5 +1,35 @@
 # What’s New
 
+## 0.6
+
++ Added support for database URLs: you can now specify the URL of the database
+  in `site.conf` by setting `[database]url`, be it MySQL, PostgreSQL or SQLite.
++ Added experimental math support, with `markdown_katex` library. The math
+  parsing can be opted out in many ways.
++ Backlinks can now be accessed for each page.
++ Spoiler tags at beginning of line now work. Just for now.
++ Removed `Upload` table.
++ Added `PageLink` table.
+
+## 0.5
+
++ Removed support for uploads. The `/upload/` endpoint now points to an info
+  page, and the “Upload image” button and gallery from home page are now gone.
++ `markdown_strikethrough` extension is no more needed. Now there are two new
+  built-in extensions: `StrikethroughExtension` and `SpoilerExtension` (the
+  last one is buggy tho).
++ Removed support for magic words (the commands between `{{` `}}`). These
+  features are now lost: `backto`, `media` and `gallery` (easily replaceable
+  with simple Markdown).
++ Added app version to site footer.
++ Added client-side drafts (they require JS enabled).
+
+## 0.4
+
+
+## 0.3
+
+
 ## 0.2
 
 + Some code refactoring.