Name device used by Synapse Admin and hook up logout button (#113)

* Name device used by Synapse Admin

* Actually logout when the logout button is pressed so that old sessions get deleted

* Fix lint

src/synapse/authProvider.js

@@ -10,6 +10,7 @@ const authProvider = {
         type: "m.login.password",
         user: username,
         password: password,
+        initial_device_display_name: "Synapse Admin",
       }),
     };
 
@@ -31,8 +32,23 @@ const authProvider = {
   // called when the user clicks on the logout button
   logout: () => {
     console.log("logout");
+
+    const logout_api_url =
+      localStorage.getItem("base_url") + "/_matrix/client/r0/logout";
+    const token = localStorage.getItem("access_token");
+
+    const options = {
+      method: "POST",
+      user: {
+        authenticated: true,
+        token: `Bearer ${token}`,
+      },
+    };
+
+    return fetchUtils.fetchJson(logout_api_url, options).then(({ json }) => {
       localStorage.removeItem("access_token");
-    return Promise.resolve();
+      localStorage.removeItem("device_id");
+    });
   },
   // called when the API returns an error
   checkError: ({ status }) => {