Yeah, thought github link was enough, but here it is:
public static void registerRender(Block block, int meta, String fileName)
{
Item item = Item.getItemFromBlock(block);
Minecraft.getMinecraft().getRenderItem().getItemModelMesher().register(item, meta,
new ModelResourceLocation(modid + ":" + fileName, "inventory"));
System.out.println(modid + ":" + fileName);
}