create docker group.

ubuntu2404-qt6-user.dockerfile

@@ -4,6 +4,7 @@ ARG USER_NAME=amass
 ARG GROUP_NAME=amass
 ARG USER_UID=1000
 ARG USER_GID=100
+ARG DOCKER_GID=281
 
 RUN set -eux; \
     if getent passwd ${USER_UID} >/dev/null; then \
@@ -13,6 +14,9 @@ RUN set -eux; \
     if ! getent group ${USER_GID} >/dev/null; then \
         groupadd -g ${USER_GID} ${GROUP_NAME}; \
     fi; \
+    if ! getent group ${DOCKER_GID} >/dev/null; then \
+        groupadd -g ${DOCKER_GID} docker; \
+    fi; \
     useradd -u ${USER_UID} -g ${USER_GID} -m -s /bin/zsh ${USER_NAME}; \
     usermod -aG sudo ${USER_NAME}; \
     usermod -aG docker ${USER_NAME}; \