Add userlink priorities and clean up

Also added Twitter as a supported website

README.md

@@ -1,3 +1,67 @@
 # upload-generator
 
-Script to help with generating gallery uploads.
+Script to generate multi-gallery upload-ready files.
+
+## Requirements
+
+- A Python environment to install dependencies (`pip install -r requirements.txt`); if unsure, create a fresh one with `virtualenv venv`.
+- LibreOffice 6.0+, making sure that `libreoffice` is in your PATH.
+
+## Usage
+
+Run with `python main.py -h` for options. Generated files are output to `./out/`.
+
+### Story files
+
+When generating an .RTF file from the source text, the script expects that LibreOffice's style has "Preformatted Text" for plaintext, and "Normal" as the intended style to replace it with. Unless you've tinkered with LibreOffice's default formatting, this won't be an issue.
+
+### Description files
+
+In order to parse descriptions, you need a configuration file (default path is `./config.json`) with the websites you wish to upload to and your username there. For example:
+
+```json
+{
+  "aryion": "MyUsername",
+  "furaffinity": "My_Username",
+  "inkbunny": "MyUsername",
+  "sofurry": "My Username",
+  "twitter": "MyUsername",
+  "weasyl": "MyUsername"
+}
+```
+
+Uppercase letters are optional. Only include your username for websites that you wish to generate descriptions for.
+
+Input descriptions should be formatted as BBCode. The following tags are accepted:
+
+```bbcode
+[b]Bold text[/b]
+[i]Italic text[/i]
+[url=https://github.com]URL link[/url]
+```
+
+There are also special tags to link to yourself or other users automatically:
+
+```bbcode
+[self][/self]
+
+[eka]EkasPortalUser[/eka]
+[fa]FurAffinityUser[/fa]
+[weasyl]WeasylUser[/weasyl]
+[ib]InkbunnyUser[/ib]
+[sf]SoFurryUser[/sf]
+[twitter]TwitterUser[/twitter]
+```
+
+`[self]` tags must always be empty. The other tags are nestable and flexible, allowing attributes to display information differently on each supported website. Some examples:
+
+```bbcode
+[eka=Lorem][/eka] is equivalent to [eka]Lorem[/eka].
+
+[fa=Ipsum]Dolor[/fa] shows Ipsum's username on FurAffinity, and Dolor everywhere else as a link to Ipsum's FA userpage.
+
+[weasyl=Sit][ib=Amet][/ib][/weasyl] will show the two user links on Weasyl and Inkbunny as expected. For other websites, the innermost tag is prioritized - Inkbunny, in this case.
+[ib=Amet][weasyl=Sit][/weasyl][/ib] is the same as above, but the Weasyl is prioritized instead.
+
+[ib=Amet][weasyl=Sit]Consectetur[/weasyl][/ib] is the same as above, but Consectetur is displayed as the username for websites other than Inkbunny and Weasyl. The Weasyl gallery is linked to in those websites.
+```