docs: add configuration information to README

README.md

@@ -2,6 +2,18 @@
 
 This is a simple terminal user interface for [vikunja](https://vikunja.io). The purpose is to allow users to manage tasks from the terminal, using their own API key. This project is not managed or affiliated with the Vikunja team.
 
+## Setup
+
+Place the following two values in a `.toml` file within your configuration files under the `vikunja-tui` directory. The instance url should not contain `api/v1`, just the base url for your instance. The api key just needs read and write access to tasks.
+
+`~/.config/vikunja-tui/config.toml
+
+```toml
+['vikunja']
+instance_url = "https://example.com"
+api_key = "<your-key-here>"
+```
+
 ## Current Features
 
 - View current tasks, with the ability to get details for any given task