No, I don’t have experience using container station for that.
But experience with container station is that it does not allways update packages frequently enough.
If you have problems with container station you can allways install Linux station amd have a full blown ubuntu Linux where you can install ruby or other packages needed.
If you have enough memory it works great if your nas supports it.
I have it running and can view films un full hd and even view them with transcoding in a web browser, or access re,otly the nas and use it as an unbuntu Linux station.
It works great.
You should not have problems for running Jekyll in it.
I have 8 GB, for running Linux station, 4gb should do if you have not plenty of services running in the nas and are not going to bloat Linux station with running apps.
I have tried virtual station, a full blown virtualization system, but it takes much more resources and is slower.
If you have just basic needs and the container gives what you need it would work with less memory requirements.
But Linux station lets you have a virtual machine you can tweak to your needs.