Put redirect link in reset password email link

This is so when users reset their password they are still
redirected to pages they were meant to visit.

This change was done specifically so everyone who is meant to see
broadcast tour sees it, but it will improve lives of all users
who wanted to visit a page on Notify but then had to reset
their password in the process

app/user/rest.py

@@ -444,7 +444,10 @@ def send_user_reset_password():
         service=service,
         personalisation={
             'user_name': user_to_send_to.name,
-            'url': _create_reset_password_url(user_to_send_to.email_address)
+            'url': _create_reset_password_url(
+                user_to_send_to.email_address,
+                next_redirect=request.get_json().get('next')
+            )
         },
         notification_type=template.template_type,
         api_key_id=None,
@@ -477,10 +480,13 @@ def get_organisations_and_services_for_user(user_id):
     return jsonify(data)
 
 
-def _create_reset_password_url(email):
+def _create_reset_password_url(email, next_redirect=None):
     data = json.dumps({'email': email, 'created_at': str(datetime.utcnow())})
-    url = '/new-password/'
-    return url_with_token(data, url, current_app.config)
+    static_url_part = '/new-password/'
+    full_url = url_with_token(data, static_url_part, current_app.config)
+    if next_redirect:
+        full_url += '?{}'.format(urlencode({'next': next_redirect}))
+    return full_url
 
 
 def _create_verification_url(user):