To set the currentUser in the field(10130). Add this script on plugins/servlet/my-groovy/rest. GET /rest/my-groovy/latest/custom/(name)?issueKey=TEST-1

JIRA Groovy Amigo Rest example.groovy

import groovy.json.JsonBuilder
import groovy.transform.BaseScript

import com.atlassian.jira.component.ComponentAccessor
import com.atlassian.jira.issue.util.DefaultIssueChangeHolder;
import com.atlassian.jira.issue.ModifiedValue;
import com.atlassian.jira.event.type.EventDispatchOption

import javax.ws.rs.core.MultivaluedMap
import javax.ws.rs.core.Response

def isUserInGroup(user, String groupName) {
    ComponentAccessor.getGroupManager().with {
        isUserInGroup(user, getGroup(groupName))
    }
}

def groups = ["jira-users"]
if(!(groups.find{isUserInGroup(currentUser, it)})){
  return Response.status(404).build()
}
queryParams = uriInfo.getQueryParameters(true)

def issueKey = queryParams.getFirst('issueKey')
if(!issueKey){
  return Response.status(404).build();
}

def cfIdDeveloper = 10130
def issue = getIssue(issueKey)
updateCustomFieldValue(issue, cfIdDeveloper, getCurrentUser(), getCurrentUser())
return Response.ok(issue.toString()).build();
   

def getCurrentUser(){
    ComponentAccessor.jiraAuthenticationContext?.user
}

def updateCustomFieldValue(issue, Long customFieldId, newValue, user){
  def customField = ComponentAccessor.customFieldManager.getCustomFieldObject(customFieldId)
    issue.setCustomFieldValue(customField, newValue)
    ComponentAccessor.issueManager.updateIssue(user, issue, EventDispatchOption.ISSUE_UPDATED, false)
}

def getIssue(String key){
    ComponentAccessor.issueManager.getIssueObject(key)
}

def getCustomFieldValue(issue, Long fieldId){
    ComponentAccessor.customFieldManager.getCustomFieldObject(fieldId)?.getValue(issue)
}