How to assign the current user id to post api in dreamfactory?

(DSP 2.1.0, Mysql DB)
I have a table as tw_venue which contains the venue details fields and added user_id field as following snapshot

The thing wants to happen to me is,The user_id field will dynamically add to the table while i'l call the api
For instance
http://localhost:81/api/v2/treat_well/_table/tw_venue
{
"resource": [
{
"name": "Rest Poinjhtd",
"type_id" : "1",
"description":"The comfort place to take rest with our care.",
"added_date":"2016-02-08"
}
]
}
here i want to append the "user_id":{user.id} by DSP while calling this api. And this is not only for this table i have many tables to add the user_id field while calling the specific apis(via POST). Where is the place to do this context in DSP @benbusse @drewpearce ?

THANKS..