should allow config override the object within an array

[hoatle]

For example default config:

    "synced_folders":[
      {
        "_id": "0",
        "type": "virtual_box",
        "host": ".",
        "guest": "/vagrant",
        "disabled": true
      },
      {
        "_id": "1",
        "type":"rsync",
        "host":"./workspace",
        "guest":"/home/vagrant/workspace",
        "rsync__exclude": [
          ".git", ".idea/", "node_modules/", "bower_components/", ".npm/"
        ]
      },
      {
        "_id":"2",
        "type":"virtual_box",
        "host":"./home/.docker",
        "guest":"/home/vagrant/.docker",
        "mount_options":[
          "dmode=775",
          "fmode=755"
        ]
      }
    ]

"_id" is required for every object within the array.

By introducing "_id" and "_op" meta key, we can override the configuration by its "_id" with its "_op" option ("a" - append, "o" - override, "r" - replace, "d" - delete).

_id exist => _op="o" by default. _op could be one of [o, r, d]
_id does not exist => _op="a" by default and only this value can be used.

_op="a": adding to the end of the array by default. To specify the index to append after, use "_idx" key with the right index (see Array.insert(index, value) Ruby API to use the right index value)

We also support force override the array key with: "r" ("r" - replace) to completely replace the array key, this is useful when we want to replace the array completely

for example:

"_r_synced_folders": []

This will replace default "synced_folders" with an empty array "[]".

"_" is reserved for teracy-dev to override the default config.

This is applied for objects within array only, for JSON object, just use its key to override.