Fixing the min naming scheme

gruntfile.js

@@ -47,12 +47,13 @@ module.exports = function (grunt) {
         grunt.file.expand({filter: 'isDirectory'}, "dist/*").forEach(function (dir) {
             grunt.file.expand({filter: 'isFile'}, dir + "/*.lua").forEach(function (file) {
                 const directory = file.substr(0, file.lastIndexOf('/'));
-                const file_name = file.substr(file.lastIndexOf('/') + 1, file.lastIndexOf('.'));
+                const file_name = file.substr(file.lastIndexOf('/') + 1);
+                const file_name_sans_ext = file_name.substr(0, file_name.lastIndexOf('.'));
 
                 const lua = fs.readFileSync(file, 'utf8');
                 const minified_contents = luamin.minify(lua);
 
-                const minified_file_name = file_name + '.min.lua';
+                const minified_file_name = file_name_sans_ext + '.min.lua';
                 const minified_file = directory + '/' + minified_file_name;
                 fs.writeFileSync(minified_file, minified_contents);
                 const file_stats = fs.statSync(file);