Fix misspelling of APP_APPLICATION___BASE_URL

This misspelling caused the environment variable value from Digital Ocean
to be not read by the app properly. I added the base_url in the production.yaml
configuration file, but it wasn't needed if I had just found and fixed this spelling.

See previous commit.

spec.yaml

@@ -17,7 +17,7 @@ services:
       - path: /
     envs:
       # Application
-      - key: APP_APPLICAITON__BASE_URL
+      - key: APP_APPLICATION__BASE_URL
         scope: RUN_TIME
         value: ${APP_URL}