Add series_name to the invoice template

[Victor]

Hi all,

been using siwapp for a while. 
To identify series_name I do use years (e.g.: series_id = 1 -> series_name = 2017).
I'd like to include it in the tags used to recall the data in the template. Something like: 

{{ invoice.series_name}}

By having something like this I would avoid editing the template according to the series_id (and series_name) I use for different years.
If the invoice belongs to 2017, for example, and I have the tag for the series_name, the year of that specific invoice would be loaded automatically (now it's hard-coded).

I hope that somebody can help me out with this.

Thanks in advance,

Victor