How could you give all players different numbers for matchmaking?

So basically I am trying to set up do a matchmaking that will give each players a target. So basically they hunt each others.

So far I have come up with this:

local players = {}
local alive = {}
local dead = {}

--------------------------


game.Players.PlayerAdded:connect(function(player)
    table.insert(players, player.Name)
end)

game.Players.PlayerRemoving:connect(function(player)
    for i=1, #players do
        if players[i] == player.Name then
            table.remove(players, i)
        end
    end
end)


function assign()
    local taken = {} -- numbers taken so far

    for i=1, #players do
    local designation = {}
        local target = math.random(1, game.Players.Numplayers)
        local take = false

        for i,v in pairs(taken) do -- check if number is taken
            if v == target then
                take = true
            end
        end

        if take == false then -- number ain't taken so player is added to list
            designation.Name = players[i]
            designation.Target = target
            table.insert(alive, designation)
        else
            -- meh 
        end

    end

end

I am unsure how to make the computer give a new number to a player if the old one is taken. And it needs to be able to give number 0 if the number of players is impair (So 1 person has no target at first). Any ideas?