single-instance: Add README details

Co-authored-by: Jonas Kruckenberg <iterpre@protonmail.com>

plugins/single-instance/README.md

@@ -1,8 +1,55 @@
-# Tauri Plugin single-instance
+![tauri-plugin-single-instance](banner.jpg)
 
-[WIP] Ensure a single instance of your tauri app is running.
+Ensure a single instance of your tauri app is running.
 
-Platforms:
-- [x] Windows
-- [x] Linux
-- [ ] macOS
+## Install
+
+There are three general methods of installation that we can recommend.
+
+1. Use crates.io and npm (easiest, and requires you to trust that our publishing pipeline worked)
+2. Pull sources directly from Github using git tags / revision hashes (most secure)
+3. Git submodule install this repo in your tauri project and then use file protocol to ingest the source (most secure, but inconvenient to use)
+
+Install the Core plugin by adding the following to your `Cargo.toml` file:
+
+`src-tauri/Cargo.toml`
+```toml
+[dependencies]
+tauri-plugin-single-instance = { git = "https://github.com/tauri-apps/plugins-workspace", branch = "dev" }
+```
+
+## Usage
+
+First you need to register the core plugin with Tauri:
+
+`src-tauri/src/main.rs`
+```rust
+use tauri::{Manager};
+
+#[derive(Clone, serde::Serialize)]
+struct Payload {
+  args: Vec<String>,
+  cwd: String,
+}
+
+fn main() {
+    tauri::Builder::default()
+        .plugin(auri_plugin_single_instance::init(|app, argv, cwd| {
+            println!("{}, {argv:?}, {cwd}", app.package_info().name);
+
+            app.emit_all("single-instance", Payload { args: argv, cwd }).unwrap();
+        }))
+        .run(tauri::generate_context!())
+        .expect("error while running tauri application");
+}
+```
+
+## Contributing
+
+PRs accepted. Please make sure to read the Contributing Guide before making a pull request.
+
+## License
+
+Code: (c) 2015 - Present - The Tauri Programme within The Commons Conservancy.
+
+MIT or MIT/Apache 2.0 where applicable.