Post install on Linux

User Docker as a non-root user

The Docker daemon binds to a Unix socket instead of a TCP port.
By default that Unix socket is owned by the user root and other users can only access it using sudo.
The Docker daemon always runs as the root user.

After installing docker, a docker group is created but no users are added to yet.
For users that need to interact with docker, you add users to it.
To create the docker group(If not existing) and add a user:
sudo groupadd docker
sudo usermod -aG docker fooUser