Change app port to 8000

Author: SakaDream

.env.sample

@@ -1,3 +1,3 @@
 APP_HOST=localhost
-APP_PORT=8080
+APP_PORT=8000
 DATABASE_URL=postgres://username:password@server/db_name

README.md

@@ -29,7 +29,7 @@ Or using [Docker](https://www.docker.com/)
 
 ## APIs
 
-### Address: **`localhost:8080`**
+### Address: **`localhost:8000`**
 
 ### `GET /api/ping`: Ping