Lint rules and flow annotations for rest of the files

server/presenters/user.js

@@ -8,8 +8,8 @@ function present(ctx: Object, user: User) {
     id: user.id,
     username: user.username,
     name: user.name,
-    avatarUrl: user.avatarUrl ||
-      (user.slackData ? user.slackData.image_192 : null),
+    avatarUrl:
+      user.avatarUrl || (user.slackData ? user.slackData.image_192 : null),
   };
 }