Add `ca-certificates` to Docker image
I just set up the Docker image of Commento with SMTP through SparkPost (seemed well reviewed). It's set up with DKIM, which I think led to the following error when I tried to sign up an owner/admin:
cannot send confirmation email: x509: failed to load system roots and no roots provided
Searching online revealed that the answer to this is to install the ca-certificates
package, which I was able to determine is not installed in the Docker container but am not sure how to install without rebuilding the container. I'd rather not do that right now, so here's an issue instead :D