Allow custom env port and remove redundancy code

[KMohZaid]

📑 Description

1. if user wants to assign custom port then they can set PORT env for docker
2. removed redundant code, it benefits alot :
   eg. no need to edit 2 files for same code change

✅ Checks

• All the tests have passed if any

[KMohZaid]

anyway, i am very thanksful to you for this repo.
no more ads and disturbance when reading blogs and ;)

medium is nice dev blogging site but too cool T_T (paywall blogger with cool heading)