Update 'assigned volunteers' checklist step

Requested via Slack.

uber/site_sections/shifts_admin.py

@@ -207,6 +207,7 @@ def staffers(self, session, department_id=None, message=''):
 
         attendees = []
         counts = defaultdict(int)
+        requested_count = 0
 
         if department_id:
             department = session.query(Department).filter_by(id=department_id).first()
@@ -217,6 +218,7 @@ def staffers(self, session, department_id=None, message=''):
             dept_filter = [] if department_id == None else [  # noqa: E711
                 Attendee.dept_memberships.any(department_id=department_id)]
             attendees = session.staffers(pending=True).filter(*dept_filter).all()
+            requested_count = len([a for a in department.unassigned_explicitly_requesting_attendees if a.is_valid])
             for attendee in attendees:
                 if session.admin_has_staffer_access(attendee) or department_id:
                     attendee.is_dept_head_here = attendee.is_dept_head_of(department_id) if department_id \
@@ -241,6 +243,7 @@ def staffers(self, session, department_id=None, message=''):
             'attendees': attendees,
             'emails': ','.join(a.email for a in attendees),
             'emails_with_shifts': ','.join([a.email for a in attendees if department_id and a.hours_here]),
+            'requested_count': requested_count,
             'checklist': checklist,
             'message': message,
         }

uber/templates/shifts_admin/staffers.html

@@ -26,6 +26,7 @@
         <ul>
             <li>that no one is assigned to your department who shouldn't be, such as problem volunteers from previous years</li>
             <li>that no one is missing who you'd expect to be assigned here, such as staffers from previous years</li>
+            <li>that you have reviewed your department's <a href="../dept_admin/requests?department_id={{ department_id }}" target="_blank">membership requests list</a> and have added any new volunteers you want</li>
         </ul>
         <input type="submit" value="I Confirm This All Looks Good" />
         </form>
@@ -37,7 +38,10 @@
 <span style="font-size:14pt ; font-weight:bold"> Staffers Assigned to This Area</span>
   (<a href="mailto:{{ c.ADMIN_EMAIL|email_only }}?bcc={{ emails }}">email these staffers</a>
   or <a href="mailto:{{ c.ADMIN_EMAIL|email_only }}?bcc={{ emails_with_shifts }}">email staffers with shifts here</a>)<b>:</b>
-<br/> <br/><a href="#attendee_form?id=None" class="btn btn-primary">Add new volunteer</a><br/><br/>
+<br/> <br/>
+<a href="#attendee_form?id=None" class="btn btn-primary">Add new volunteer</a>
+<a href="../dept_admin/requests?department_id={{ department_id }}" class="btn btn-info" target="_blank">Review membership requests{% if requested_count %} ({{ requested_count }}){% endif %}</a>
+<br/><br/>
 
 <table class="table table-striped datatable">
 <thead><tr>