Trigger Adds SDocs Permission Set to Newly Created Community Users

/* This code automatically assigns the S-Docs User permission set
to newly created community users */
trigger AssignSDocsUserPermissionSet on User (after insert) {
   Id sdocsUserPermissionSetID = [SELECT Id, Name FROM PermissionSet WHERE Name='SDocs_User'].Id;
   Id communityUserProfileID = [SELECT Id FROM Profile WHERE Name='NAME_OF_COMMUNITY_USER_PROFILE_GOES_HERE'].Id;
   List<PermissionSetAssignment> permissionSetAssignments = new List<PermissionSetAssignment>();
   for (User user : trigger.new) {
       if (UserInfo.getProfileId() == communityUserProfileID) {
           PermissionSetAssignment psa = new PermissionSetAssignment(
               PermissionSetId=sdocsUserPermissionSetID,
               AssigneeId=user.Id );
           permissionSetAssignments.add(psa);
       }
   }
   upsert permissionSetAssignments;
}