Save collapsed sections to state

When you refresh or navigate to a new page and back, your collapsed sections will be as you set them.

store/mutations.js

@@ -7,6 +7,12 @@ export default {
     gql[attribute] = value
   },
 
+  setCollapsedSection({ theme }, value) {
+    theme.collapsedSections.includes(value)
+      ? (theme.collapsedSections = theme.collapsedSections.filter(section => section !== value))
+      : theme.collapsedSections.push(value)
+  },
+
   addGQLHeader({ gql }, object) {
     gql.headers.push(object)
   },