Changed routes to id's os sub_types

frontend/src/components/student/StudentLayout.vue

@@ -52,8 +52,8 @@
       submissionNavItems: function () {
         return this.$store.state.studentPage.submissions.map((sub, index) => {
           return {
-            name: sub.type,
-            route: `/student/submission/${index}`
+            name: sub.type_name,
+            route: `/student/submission/${sub.type_id}`
           }
         })
       }

frontend/src/components/student/SubmissionList.vue

@@ -4,12 +4,13 @@
       hide-actions
       :headers="headers"
       :items="submissions"
+      item-key="type"
     >
       <template slot="items" slot-scope="props">
-        <td>{{ props.item.type }}</td>
+        <td>{{ props.item.type_name }}</td>
         <td class="text-xs-right">{{ props.item.score }}</td>
         <td class="text-xs-right">{{ props.item.full_score }}</td>
-        <td class="text-xs-right"><v-btn :to="`submission/${props.index}`" color="orange lighten-2">View</v-btn></td>
+        <td class="text-xs-right"><v-btn :to="`submission/${props.item.type_id}`" color="orange lighten-2">View</v-btn></td>
       </template>
     </v-data-table>
     <v-alert color="info" value="true">