add user to docker group

# Creates docker group
sudo groupadd docker

# Add your user to the docker group
sudo usermod -aG docker $USER

# Log out and log back in so that your group membership is re-evaluated
# GNOME example
gnome-session-quit

$ sudo groupadd docker
$ sudo usermod -aG docker $USER
$ newgrp docker 

# my case solution
sudo setfacl -m user:$USER:rw /var/run/docker.sock

#other solution
sudo usermod -aG docker $USER

#an other solution
sudo groupadd docker
sudo gpasswd -a $USER docker
docker run hello-world

sudo usermod -aG docker $USER   #$USER is your username

FROM alpine:latest
RUN apk --no-cache update \
    && apk --no-cache add sudo
copy run.sh /usr/local/
RUN addgroup -S cassandra && adduser -S cassandra -G cassandra
RUN chown -R cassandra:cassandra /home/cassandra/
RUN echo 'cassandra  ALL=(ALL) /bin/su' >>  /etc/sudoers
USER cassandra
ENTRYPOINT [ "sh","/usr/local/run.sh"]