How to convert groovy into script runner rest end point

[Ipsita Dash]

How to make this below groovy script to rest end point, so that i can call it externally as a JIRA rest api.

import com.atlassian.jira.bc.security.login.LoginService
import com.atlassian.jira.component.ComponentAccessor
import com.atlassian.jira.user.util.UserManager
import com.atlassian.jira.user.util.UserUtil

def result = ""

String groupname = "jira-administrators";
String username = "SVC-OneHygieia";

UserUtil userUtil = ComponentAccessor.userUtil;
userUtil.addUserToGroup(userUtil.getGroup(groupname) ,userUtil.getUser(username))
result = result + "Added " + username + " from " + groupname

result

Thanks,

Ipsita Dash