Set slug default to null instead of empty string (#232)

* Initial plan

* Change slug default from empty string to null

Co-authored-by: cubap <1119165+cubap@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: cubap <1119165+cubap@users.noreply.github.com>

Author: Copilot

controllers/crud.js

@@ -15,7 +15,7 @@ import { _contextid, idNegotiation, generateSlugId, ObjectID, createExpressError
  * */
 const create = async function (req, res, next) {
     res.set("Content-Type", "application/json; charset=utf-8")
-    let slug = ""
+    let slug = null
     if(req.get("Slug")){
         let slug_json = await generateSlugId(req.get("Slug"), next)
         if(slug_json.code){

controllers/release.js

@@ -23,7 +23,7 @@ import { _contextid, ObjectID, createExpressError, getAgentClaim, parseDocumentI
 const release = async function (req, res, next) {
     let agentRequestingRelease = getAgentClaim(req, next)
     let id = req.params["_id"]
-    let slug = ""
+    let slug = null
     let err = {"message":""}
     let treeHealed = false
     if(req.get("Slug")){