Store Package Control/User
You only need to add the ~/Library/Application Support/Sublime Text 3/Package Control/User/
(or on Windows: C:\Users\{username}\AppData\Roaming\Sublime Text 3\Packages\User
) directory.
From https://packagecontrol.io/docs/syncing
The proper solution is to install Package Control on all machines and then to sync only the Packages/User/ folder. This folder contains the Package Control.sublime-settings file, which includes a list of all installed packages. If this file is copied to another machine, the next time Sublime Text is started, Package Control will install the correct version of any missing packages.
Steps to set it up
Create a new repo on github, name it something like "sublime-prefs", then run these commands:
cd ~/Library/Application\ Support/Sublime\ Text\ 3/Packages/User
git init
git add Package\ Control.sublime-settings
git commit -am "settings from from <device name>"
git remote add origin https://github.com/<github name>/<repo name>.git
git push -u origin master
Pulling down to other machines...
Quit Sublime Text 3, then run these commands (using answer from How do I clone into a non-empty directory?):
cd ~/Library/Application\ Support/Sublime\ Text\ 3/Packages/User/
git init
git remote add origin https://github.com/<github name>/<repo name>.git
rm Package\ Control.sublime-settings
git fetch
git checkout -t origin/master