How do I create a custom Enum?

Let's say I have property that I only want to have a variable number of states. For example, let's take an elemental attribute. We've got Fire, Grass, Water, Earth, and Wind.

Would I create a separate object for this purpose which retains a value and reference table?

local Type = {}
function Type.new(input) --input is a number or string in this case.
	local o = {}
	local o.Value = 0;
	local typeChart = {"Fire", "Grass", "Water", "Earth", "Wind"}
	
	if input:IsA("Number") then --Don't know exactly how to determine Data Types. If you can fill me in on this, please do.
		o.Value = input;
	else
		for i, v in pairs(typeChart)
			if input == v then
				o.Value = i;
				break
			end	
		end
	end
	
	function o:getString() -- Returns the String associated with o.Value in the typeChart
	function o:equals(type) -- Returns true or false when comparing two Type objects
	
	return o;
end

Or is there a simpler way of doing this?