set appdmg package optional

gruntfile.js

@@ -3,7 +3,9 @@ const ChildProcess = require('child_process')
 const packager = require('electron-packager')
 const archiver = require('archiver')
 const fs = require('fs')
-const appdmg = require('appdmg')
+if (process.platform === 'darwin') {
+  const appdmg = require('appdmg')
+}
 
 module.exports = function (grunt) {
   var initConfig = {

package.json

@@ -33,7 +33,6 @@
   "homepage": "https://github.com/Rokt33r/codexen-app#readme",
   "dependencies": {
     "@rokt33r/node-ipc": "^5.0.4",
-    "appdmg": "^0.3.5",
     "devicon": "^2.0.0",
     "electron-gh-releases": "^2.0.2",
     "font-awesome": "^4.3.0",
@@ -74,6 +73,9 @@
     "webpack": "^1.12.2",
     "webpack-dev-server": "^1.12.0"
   },
+  "optionalDependencies": {
+    "appdmg": "^0.3.5"
+  },
   "standard": {
     "ignore": [],
     "globals": [