With the 0.2.6 update, I added a bit of a slightly nicer mod support backend.
It's POLYMOD, which is made by Lars Doucet: https://github.com/larsiusprime/polymod
You may have noticed that there's a new folder in the assets. MODS. Within it you will see 2 files. modList.txt, and a folder called introMod. modList.txt will load any folder into the game. Put the folder you want to load into a new line in modList.txt, and reboot the game.
Now you may be wondering, what do I put in the folder? Well later down it'll get a bit more complicated, especially as I'll make the IN-GAME mod loader nicer.