Add Google example

examples/google.rs

@@ -0,0 +1,17 @@
+extern crate inth_oauth2;
+
+use inth_oauth2::client::Client;
+use inth_oauth2::provider::Google;
+
+fn main() {
+    let client = Client::<Google>::new(
+        Default::default(),
+        "143225766783-ip2d9qv6sdr37276t77luk6f7bhd6bj5.apps.googleusercontent.com",
+        "3kZ5WomzHFlN2f_XbhkyPd3o",
+        Some("urn:ietf:wg:oauth:2.0:oob")
+    );
+
+    let auth_uri = client.auth_uri(Some("https://www.googleapis.com/auth/userinfo.email"), None)
+        .unwrap();
+    println!("{}", auth_uri);
+}