add treacle_notify crate skeleton

Cargo.toml

@@ -1,2 +1,5 @@
 [workspace]
-members = ["treacle"]
+members = [
+    "treacle",
+    "treacle_notify",
+]

treacle_notify/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "treacle_notify"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+notify = "6.1.1"
+treacle = { version = "0.1.0", path = "../treacle" }

treacle_notify/src/lib.rs

@@ -0,0 +1,14 @@
+pub fn add(left: usize, right: usize) -> usize {
+    left + right
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn it_works() {
+        let result = add(2, 2);
+        assert_eq!(result, 4);
+    }
+}