Redis db is created in my local computer instead of inside the container!

I’m running docker for linux and using an ubuntu image. I installed redis as a service

here’s my dockerfile: https://github.com/redis/redis/files/6384165/Dockerfile.zip

here’s how i start the docker image:

docker run -it --rm --net=host imagename

Here’s how i start redis in the Dockerfile:
CMD redis-server /etc/redis/redis.conf && /bin/bash

now whenever i make changes to the database and runredis-cli SAVE or redis-cli BGSAVE i expect to find a dump.rdb file generated in /var/lib/redis but instead i get nothing and dump.rdb is saved to my local /var/lib/redis !!
these two lines are from my redis.conf in docker:

dbfilename dump.rdb
dir /var/lib/redis 

when i run without --network==host i find dump.rdb inside the container!!

also any changes in redis config file in docker are affecting the host!!

In docker:

redis-cli config set dir "/"

on the host:

root@alya:/ redis-cli config get dir
1) "dir"
2) "/"

How do i get redis to generate dump.rdb inside the docker container and what is causing this behavior?