A program is under development to keep track of a clubs members

Keep a chart with you

Explanation:

You could right something along the lines of:

To keep track of the members in the club, I'll(we'll) have them write their names down on a chart so we don't forget. I(we) could also just do a thing where I(we) plan everything out beforehand and I(we) have been keeping track of the members.

You could right something along the lines of:

Since the program is under development, I(we) could tell everyone in the club to put their names on a spreadsheet and I(we) could start developing the program further that way.