/*
* This example script  console script updates a multi user picker field on an issue.
* "All right, title and interest in this code snippet shall remain the exclusive intellectual property of Adaptavist Group Ltd and its affiliates. Customers with a valid ScriptRunner
* license shall be granted a  non-exclusive, non-transferable, freely revocable right to use this code snippet only within their own instance of Atlassian products. This licensing notice cannot be removed or
* amended and must be included in any circumstances where the code snippet is shared by You or a third party." 
*/

// Specify the issue key of the issue to update below
def issue = "<issueKeyHere>"

// Specify the ID of the custcom field here
def MultiUserField = "<CustomFieldIdHere>".toString()


// The rest call to update the multi user picker field. 
// Note: This script must be run as the ScriptRunner add on user
def setMultiUserPicker = put("/rest/api/2/issue/"+ issue)
        .header('Content-Type', 'application/json')
        .queryString("overrideScreenSecurity", Boolean.TRUE)
        .body([
            // Specify the update structure to update the Multi Select list field and its Array List Data Structure that it uses
            update:
                [
                    (MultiUserField): [
                        // Specify the add commands to add each user into the Array List structure for the field using their accountId
                        // Comma seperate the add commend for each user you want to add using their accountId
                        [add: [accountId: "<AccountIDHere>"]],
                        [add: [accountId: "<AccountIDHere>"]]
                        ]
                
                ]
        ])
        .asString()
        .body
        
return "Issue with the key of ${issue} updated with the Multi User Picker Field set on it"