Implement logout

Also introduce a library to handle cookies

app/src/logout.rs

@@ -0,0 +1,54 @@
+use crate::cookies::delete_cookie;
+use yew::prelude::*;
+use yew::services::ConsoleService;
+
+pub struct LogoutButton {
+    link: ComponentLink<Self>,
+    on_logged_out: Callback<()>,
+}
+
+#[derive(Clone, PartialEq, Properties)]
+pub struct Props {
+    pub on_logged_out: Callback<()>,
+}
+
+pub enum Msg {
+    Logout,
+}
+
+impl Component for LogoutButton {
+    type Message = Msg;
+    type Properties = Props;
+
+    fn create(props: Self::Properties, link: ComponentLink<Self>) -> Self {
+        LogoutButton {
+            link: link.clone(),
+            on_logged_out: props.on_logged_out,
+        }
+    }
+
+    fn update(&mut self, msg: Self::Message) -> ShouldRender {
+        match msg {
+            Msg::Logout => match delete_cookie("user_id") {
+                Err(e) => {
+                    ConsoleService::error(&e.to_string());
+                    false
+                }
+                Ok(()) => {
+                    self.on_logged_out.emit(());
+                    true
+                }
+            },
+        }
+    }
+
+    fn change(&mut self, _: Self::Properties) -> ShouldRender {
+        false
+    }
+
+    fn view(&self) -> Html {
+        html! {
+            <button onclick=self.link.callback(|_| { Msg::Logout })>{"Logout"}</button>
+        }
+    }
+}