type RessourcesIdManager
    tools :: Array{String, 1}
    materials :: Array{String, 1}
end

function get_tool_id_of(x::RessourcesIdManager, name::String)
    for i = 1:length(x.tools)
        if name == x.tools[i]
            return i
        end
    end
end

function get_material_id_of(x::RessourcesIdManager, name::String)
    for i = 1:length(x.materials)
        if name == x.materials[i]
            return i
        end
    end
end

tools = ["Sickle"]
materials = ["Wood", "Corn"]
ressources_id_manager = RessourcesIdManager(tools, materials)