feat: support runas user

Signed-off-by: Jan Lauber <jan.lauber@protonmail.ch>

Dockerfile

@@ -4,14 +4,22 @@ FROM google/cloud-sdk:latest
 # Install MySQL client
 RUN apt-get update && apt-get install -y default-mysql-client
 
-# Create a directory for the backup
+# Create a non-root user and group
+# Note: Ensure the user and group IDs do not conflict with IDs on the host or in other containers
+RUN groupadd -r mysqlbackup -g 3000 && \
+    useradd -r -g mysqlbackup -u 1001 -m -d /backup mysqlbackup
+
+# Create a directory for the backup and set permissions
 WORKDIR /backup
+RUN chown mysqlbackup:mysqlbackup /backup
 
 # Copy the backup script into the container
 COPY backup.sh /backup/backup.sh
-
-# Make the backup script executable
 RUN chmod +x /backup/backup.sh
+RUN chown mysqlbackup:mysqlbackup /backup/backup.sh
+
+# Use the non-root user to run the container
+USER mysqlbackup
 
 # Set the entry point to the backup script
 ENTRYPOINT ["/backup/backup.sh"]