Update modinfo to include gitignored files.

modinfo.lua

@@ -8,4 +8,12 @@ return {
 	remote_file_id = 776095610,
 	readme = "readme.md",
 	steambb = "steam.bbcode",
+	-- stlrel uses git-archive, which means that any files in
+	-- .gitignore are not included. If you want to include any,
+	-- you need to add relative paths here.
+	zip = {
+		-- include all files from .gitignore
+		gitignore = true,
+		files = {} -- can contain relative file paths
+	}
 }