Fix galleryCreate mutation (#1004)

graphql/documents/mutations/gallery.graphql

@@ -1,26 +1,7 @@
 mutation GalleryCreate(
-  $title: String!,
-  $details: String,
-  $url: String,
-  $date: String,
-  $rating: Int,
-  $organized: Boolean,
-  $scene_id: ID,
-  $studio_id: ID,
-  $performer_ids: [ID!] = [],
-  $tag_ids: [ID!] = []) {
+  $input: GalleryCreateInput!) {
 
-  galleryCreate(input: {
-    title: $title,
-    details: $details,
-    url: $url,
-    date: $date,
-    rating: $rating,
-    scene_id: $scene_id,
-    studio_id: $studio_id,
-    tag_ids: $tag_ids,
-    performer_ids: $performer_ids
-    }) {
+  galleryCreate(input: $input) {
       ...GalleryData
   }
 }