I apologize as I may have posted this in the wrong category. It may fit better here. If so, would a mod please delete the original:
I'm relatively new to WordPress, but I'm a programmer for a living. Because of that, I don't like reinventing the wheel. Recently, I downloaded a plugin. I can modify this post to say what the plugin was if needed, but this is more generalized. This plugin tracks items, and creates newsletters based on those tracked items.
One of those items is Gender. Since the visitors I get are sometimes couples, they share email addresses(email is a required field), therefore I cant demand of them to each have an email, so in the Gender Field, I added Couple, tested it, and it works great. Adds an m for male, f for female, and a c for couple to the plugin's customized table in the WordPress Database.
Recently, the plugin had an update, and I updated it. Because I modified pieces in the plugin's core files, the update overwrote the custom field I added, causing me to have to re-add the custom work I did. Can someone tell me what the best approach is to customizing the plugin, while keeping it up to date? Is there a hook I can use/add that will accomplish what I'm asking etc.?