Fix Windows 10 Docker json

.gitignore

@@ -16,3 +16,4 @@
 tmp
 /issues/
 *.iso
+path-to.vmx

README.md

 # My Retina Windows Templates for Packer
+[![Build status](https://ci.appveyor.com/api/projects/status/76pea1oexae5ca05?svg=true)](https://ci.appveyor.com/project/StefanScherer/packer-windows)
 
 ### Introduction
 

windows_10_docker.json

@@ -62,6 +62,6 @@
     }
   ],
   "variables": {
-    "source_path": "~/.vagrant.d/boxes/windows_10/0/vmware_desktop/windows_10.vmx"
+    "source_path": "path-to.vmx"
   }
 }