added Docker

Dockerfile

@@ -218,7 +218,28 @@ RUN apt update && \
 # Install CS50 library
 RUN curl https://packagecloud.io/install/repositories/cs50/repo/script.deb.sh | bash && \
     apt update && \
-    apt install --yes libcs50
+    apt install libcs50
+
+
+# Install Docker
+# https://docs.docker.com/engine/install/ubuntu/
+# https://docs.docker.com/engine/install/linux-postinstall/
+RUN apt update && \
+    apt install --no-install-recommends --no-install-suggests --yes \
+        ca-certificates \
+        curl && \
+    install -d /etc/apt/keyrings -m 0755 && \
+    curl --fail --location --show-error --silent https://download.docker.com/linux/ubuntu/gpg -o /etc/apt/keyrings/docker.asc && \
+    chmod a+r /etc/apt/keyrings/docker.asc && \
+    echo "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.asc] https://download.docker.com/linux/ubuntu $(. /etc/os-release && echo "$VERSION_CODENAME") stable" | tee /etc/apt/sources.list.d/docker.list > /dev/null && \
+    apt update && \
+    sudo apt install --no-install-recommends --no-install-suggests --yes \
+        containerd.io \
+        docker-buildx-plugin \
+        docker-ce \
+        docker-ce-cli \
+        docker-compose-plugin && \
+    groupadd --force docker
 
 
 # Install Python packages
@@ -260,7 +281,8 @@ RUN useradd --home-dir /home/ubuntu --shell /bin/bash ubuntu && \
     echo "ubuntu ALL=(ALL) NOPASSWD:ALL" >> /etc/sudoers && \
     echo "Defaults umask_override" >> /etc/sudoers && \
     echo "Defaults umask=0022" >> /etc/sudoers && \
-    sed --expression="s/^Defaults\tsecure_path=.*/Defaults\t!secure_path/" --in-place /etc/sudoers
+    sed --expression="s/^Defaults\tsecure_path=.*/Defaults\t!secure_path/" --in-place /etc/sudoers && \
+    usermod --append --groups docker ubuntu
 
 
 # Version the image (and any descendants)

Makefile

@@ -13,7 +13,7 @@ rebuild:
 	$(MAKE) squash
 
 run:
-	docker run --env LANG="$(LANG)" --interactive --publish-all --rm --security-opt seccomp=unconfined --tty --volume "$(PWD)":/home/ubuntu cs50/cli bash --login || true
+	docker run --env LANG="$(LANG)" --interactive --privileged --publish-all --rm --security-opt seccomp=unconfined --tty --volume "$(PWD)":/home/ubuntu cs50/cli bash --login || true
 
 squash: depends
 	docker images cs50/cli