tsk-5: Add contact (#15)

Closes #5

Reviewed-on: phoenix/textsender#15
Co-authored-by: phoenix <kundeng00@pm.me>
Co-committed-by: phoenix <kundeng00@pm.me>

src/constants/app.js

@@ -1,2 +1,4 @@
 export const DATA_KEY_ACCESS_TOKEN = 'access_token';
 export const DATA_KEY_REGISTERED_USER_ID = 'registered_user_id';
+export const DATA_KEY_USER_ID = 'user_id';
+export const DATA_KEY_ADDED_CONTACT_ID = 'added_contact_id';