A better, but more difficult (for beginners) way to do that, is to edit the fstab file. That file contains the information of where to mount your partitions when you boot. I don't think that putting a symbolic link would allow for automatic mounting of the partition with the music on it. So before using your music I think you would have to mount your partition each time, or basically Ubuntu will think that the files don't exist.
Before editing your fstab file you should make a backup of it in case something goes wrong.
If you need to revert the changes for any reason use this:
sudo cp /etc/fstab /etc/fstab.old
Then you need the UUID for your music partition. I'm assuming you know the partition number of your music partition. For this example I'll use /dev/sda5.
sudo mv /etc/fstab.old /etc/fstab
Run the command
and you should get an output that has the UUID's highlighted followed by their partition number.
ls -l /dev/disk/by-uuid/
For example it might look like
This part 'b6cce33a-f9c3-4064-84ce-98d7d8b3a1fb' is what you want for /dev/sda5 in this example.
lrwxrwxrwx 1 root root 10 May 13 12:31 a3ca2474-5ec5-4360-a351-4abf127db18e -> ../../sda6
lrwxrwxrwx 1 root root 10 May 13 12:31 b6cce33a-f9c3-4064-84ce-98d7d8b3a1fb -> ../../sda5
Then you'll want to open up the fstab file for editing. Make sure you have the original backed up!
You should have something like this.
gksudo gedit /etc/fstab
Then you just need to add your partition
# /etc/fstab: static file system information
# <file system> <dir> <type> <options> <dump> <pass>
UUID=4e450a74-d94d-45af-870e-1e156b9cf99a / ext4 rw,relatime,data=ordered 0 1
UUID=7d545aa0-da1a-44c7-9a22-a78a30d5e453 /boot ext4 rw,relatime,data=ordered 0 2
# /dev/sda1 LABEL=EFI
UUID=70D6-1701 /boot/efi vfat rw,relatime,fmask=0022,dmask=0022,codepage=437,iocharset=iso8859-1,shortname=mixed,errors=remount-ro 0 2
You should be able to just follow the other entries, just add yours onto the end like:
Except where it says UUID= you want to make sure you put in the UUID you got from the earlier command and make sure you change the <your_username> to whatever your commandline username is.
UUID=<your_UUID> /home/<your_username>/music ext4 rw,relatime,data=ordered 0 2
Then all you have to do is reboot and you should have the music partition mounted at /music in your home directory.