Add Imgur example

examples/imgur.rs

@@ -0,0 +1,16 @@
+extern crate inth_oauth2;
+
+use inth_oauth2::client::Client;
+use inth_oauth2::provider::Imgur;
+
+fn main() {
+    let client = Client::<Imgur>::new(
+        Default::default(),
+        "505c8ca804230e0",
+        "c898d8cf28404102752b2119a3a1c6aab49899c8",
+        Some("https://cmcenroe.me/oauth2-paste/")
+    );
+
+    let auth_uri = client.auth_uri(None, None).unwrap();
+    println!("{}", auth_uri);
+}