postgresql – postgres – c = does not work for postgres 11 in docker

I run a Postgres inside a docker. I want to change the default Postgres configuration so I run:

Docker container executed -d postgres -c max_connections = 200 -c shared_buffers = 1GB -c effect_cache_size = 3GB -c maintenance_work_mem = 256 MB -c checkpoint_completion_target = 0.7 -c wal_buffers = 16 MB 

But when I connect to Postgres running:

    docker exec -it container_name psql

And then the result of:

SHOW max_connections;


(1 row)

And it's not fair max_connections. None of the settings are changed. And I do not know what's the problem with what I'm doing?