Add workflow with no data ends in Undefined index exception

[raffis]

Describe the bug

[07-Jun-2019 06:18:26] WARNING: [pool www] child 465 said into stdout: "2019-07-06 06:18:26 [Tubee\Bootstrap\ContainerBuilder,DEBUG]: Undefined index: data in /usr/share/tubee/src/lib/Workflow/Factory.php:179  "
[07-Jun-2019 06:18:26] WARNING: [pool www] child 465 said into stdout: "2019-07-06 06:18:26 [Tubee\Rest\Middlewares\ExceptionHandler,ERROR]: uncaught exception Undefined index: data]  [object] (ErrorException(code: 0): Undefined index: data at /usr/share/tubee/src/lib/Workflow/Factory.php:179)"

To Reproduce

Add workflow without data field:

{
    "_id" : ObjectId("5cf927fa651dfc01da7ffc92"),
    "name" : "create-update",
    "secrets" : [ ],
    "kind" : "Workflow",
    "namespace" : "ns",
    "collection" : "accounts",
    "endpoint" : "im-mssql",
    "created" : ISODate("2019-06-06T14:49:30.296Z"),
    "changed" : ISODate("2019-06-06T14:49:30.296Z"),
    "version" : 1
}

Expected behavior

The default should be used for data. Or maybe data should be required since an empty data does not really make sense.

Environment

• tubee server version: v1.0.0-beta20
• tubectl version: [e.g. v1.0.0]
• MongoDB Version: [e.g. v3.4.18]
• PHP Version [e.g. v7.2.1]

Additional context

Add any other context about the problem here.