Add Arch Linux dependencies to readme

README.md

@@ -4,6 +4,11 @@
 
 ## Setup
 
+`jon` is a Python WSGI application written using Flask.
+This means you'll have to install a bunch of Python packages to get up and running.
+
+### Dependencies
+
 ```
 pip install -r requirements.txt
 ```
@@ -11,6 +16,14 @@ pip install -r requirements.txt
 You should probably use a virtualenv for that.
 I develop `jon` using Python 3.10 but it should work with older versions as well.
 
+#### Arch Linux
+
+If you're on Arch, these packages are required for running the server:
+
+```
+python python-flask python-flask-login python-psycopg2
+```
+
 ### Building Frontend JS
 
 Most of jon works without JS but there are some features that require it.