fix survey service when no answer; update develop.md file

DEVELOP.md

@@ -295,6 +295,15 @@ This module provides the services, views and javascript for schools to submit th
 - application module
 - `zendframework/zend-inputfilter`: ^2.0
 
+### tpe_survey
+
+This module overrides staff view of schools module. It allows school user to submit 
+information about teachers using IT in education.
+
+#### Dependencies
+
+ - schools module
+
 ## ER diagram
 
 ![ER diagram](https://github.com/eellak/gredu_labs/blob/develop/data/db/er.png)

module/tpe_survey/src/Service/SurveyService.php

@@ -18,6 +18,9 @@ class SurveyService implements SurveyServiceInterface
     public function getAnswers($teacherId)
     {
         $bean                  = R::findOne('tpesurvey', 'teacher_id = ?', [$teacherId]);
+        if (null === $bean) {
+            return;
+        }
         $data                  = $bean->export();
         $data['assets_in_use'] = explode('|', $data['assets_in_use']);
         if (!$data['assets_in_use']) {