fixed BUG-73, missing import

BUGs

@@ -1,4 +1,4 @@
-### Next: 73
+### Next: 74
 BUG-56: when making a viewing list of AI:mich, (any search?) and going past the page_size, it gets the wrong data from the DB for the 'next' entry
 BUG-60: entries per page (in folders view) ignores pagesize, and this also contributes to BUG-56 I think
 BUG-61: in Fullscreen mode and next/prev dropped out of FS when calling /viewlist route
@@ -8,4 +8,3 @@ BUG-69: when moving a directory (maybe files???) it creates new destination dire
 BUG-70: when a dir is a match and a file is a match (common with our date-based matching), then we get 2 answers in the search
 BUG-72: when re-scanning import dir, I always regen hash for 20201225_181843.jpg - why?
         -- also happened for a lot of storage photos, see job: 909
-BUG-73: NameError NameError: name 'url_for' is not defined (saving settings)

settings.py

@@ -1,6 +1,6 @@
 from wtforms import SubmitField, StringField, FloatField, HiddenField, validators, Form, SelectField
 from flask_wtf import FlaskForm
-from flask import request, render_template, redirect
+from flask import request, render_template, redirect, url_for
 from main import db, app, ma
 from sqlalchemy import Sequence
 from sqlalchemy.exc import SQLAlchemyError