On the latest kernels the SSD disks are automatically detected. This is how you verify:
Replace sda with your hard drive path.
$ cat /sys/block/sda/queue/rotational
You will a number as an output
1 means you have a HDD
0 means you have a SSD
This method needs root access and internet.
If you do not have the smartctl tool, you have to install it, like this:
$ sudo apt-get install smartmontools
Find out if you have a SSD or a normal HDD:
$ sudo smartctl -a /dev/sda
If you get this output, it means you have an SSD, else, it is an HDD:
Rotation Rate: Solid State Device