Upload Definition Content

Upload/Save the content of a definition.

POST `/revisions/:id/data` (Command: `upload_definition`)

Parameter	Type	Required	Description
`engine`	string	Yes	Must be `workflow_blobhub`.
`command`	string	Yes	Must be `upload_definition`.
`definition_id`	string	Yes	The ID of the definition.
`definition`	object	Yes	The JSON body of the definition.

Returns an empty JSON object upon success.

{
  "engine": "workflow_blobhub",
  "command": "upload_definition",
  "definition_id": "def_001",
  "definition": {
    "steps": [...]
  }
}