Add another example (#32)

examples/customer.rs

@@ -0,0 +1,31 @@
+use serde::{Deserialize, Serialize};
+use superstruct::superstruct;
+
+#[superstruct(
+    variants(V1, V2, V3),
+    variant_attributes(derive(Deserialize, Serialize))
+)]
+#[derive(Deserialize, Serialize)]
+#[serde(untagged)]
+pub struct Customer {
+    pub name: String,
+    #[superstruct(only(V1), partial_getter(rename = "age_v1"))]
+    pub age: String,
+    #[superstruct(only(V2), partial_getter(rename = "age_v2"))]
+    pub age: u64,
+    #[superstruct(only(V3))]
+    pub dob: u64,
+    #[superstruct(only(V2, V3))]
+    pub favourite_colour: String,
+}
+
+fn main() {
+    let customer = Customer::V3(CustomerV3 {
+        name: "Michael".into(),
+        dob: 0,
+        favourite_colour: "purple".into(),
+    });
+    assert_eq!(customer.name(), "Michael");
+    assert_eq!(customer.dob(), Ok(&0));
+    assert_eq!(customer.favourite_colour().unwrap(), "purple");
+}