Docker - How can run the psql command in the postgres container?

Question

I would like to use the psql in the postgres image in order to run some queries on the database. But unfortunately when I attach to the postgres container, I got that error

Answer 1

RUN /etc/init.d/postgresql start &&\
    psql --command "CREATE USER docker WITH SUPERUSER PASSWORD 'docker';" &&\
    createdb -O docker docker &&\