gap_value=10

gap=gap_value

awful.tag.add("First tag", {
    icon               = "/path/to/icon1.png",
    layout             = awful.layout.suit.tile,
    master_fill_policy = "master_width_factor",
    gap_single_client  = true,
    gap                = 15,
    screen             = s,
}

awful.tag.new (names, screen, layout)
Create a set of tags and attach it to a screen.

names The tag name, in a table
screen The tag screen, or 1 if not set.
layout The layout or layout table to set for this tags by default.

function tag.new(names, screen, layout)
    screen = get_screen(screen or 1)
    local tags = {}
    for id, name in ipairs(names) do
        table.insert(tags, id, tag.add(name, {screen = screen,
                                            layout = (layout and layout[id]) or
                                                        layout}))
        -- Select the first tag.
        if id == 1 then
            tags[id].selected = true
        end
    end

    return tags
end