To setup FastDL all we need to do is make a Lua File, To do so go to your File Manager and Navigate to garrysmod/lua/autorun/server and click “New File”
and name the new file workshop.lua
Now click the pencil to edit
and add the following code
resource.AddWorkshop("ADDONID")
You will need to add this line of code for every Addon that you want the end-user to download.
To get your AddonID just copy the link of the Addon and grab the numbers after id=
So if my Addon link is http://steamcommunity.com/sharedfiles/filedetails/?id=99999999 my AddonID would be 99999999.
Now save your workshop.lua, Restart your server and then users will auto-download the Addons you put in your workshop.lua