Add collections (#172)

src/schema.graphql

@@ -41,6 +41,8 @@ type Query {
   signedFileUploadURL(config: SignedUploadURLInput): SignedUploadURL
     @cacheControl(maxAge: 0)
   translate(input: TranslateInput!): StringResult!
+  collections: [Collection]
+  collection(id: Int!): Collection
 }
 
 type HealthCheck {
@@ -260,6 +262,7 @@ type Product {
   printProducts(groups: [ProductGroup]): [PrintProduct]
   blacklisting: [ProductBlacklist]
   categories: [Category]
+  collections: [Collection]
   designerId: Int
   designer: Designer
   keywords: [Keyword]
@@ -553,3 +556,9 @@ type Mutation {
   ): StringResult
   massUpdatePublishingDate(productIds: [Int]!, date: DateTime!): StringResult
 }
+
+type Collection {
+  id: ID!
+  name: String!
+  productIds: [Int!]!
+}