GraphQL schema file added, fix of PostResolver

- graphqls was missing
- author in Post is mandatory

spring-boot-modules/spring-boot-libraries/src/main/java/com/baeldung/graphql/PostResolver.java

@@ -1,7 +1,5 @@
 package com.baeldung.graphql;
 
-import java.util.Optional;
-
 import com.coxautodev.graphql.tools.GraphQLResolver;
 
 public class PostResolver implements GraphQLResolver<Post> {
@@ -11,7 +9,7 @@ public class PostResolver implements GraphQLResolver<Post> {
         this.authorDao = authorDao;
     }
 
-    public Optional<Author> getAuthor(Post post) {
-        return authorDao.getAuthor(post.getAuthorId());
+    public Author getAuthor(Post post) {
+        return authorDao.getAuthor(post.getAuthorId()).orElseThrow(RuntimeException::new);
     }
 }

spring-boot-modules/spring-boot-libraries/src/main/resources/graphql/post.graphqls

@@ -0,0 +1,24 @@
+type Post {
+    id: ID!
+    title: String!
+    text: String!
+    category: String
+    author: Author!
+}
+
+type Author {
+    id: ID!
+    name: String!
+    thumbnail: String
+    posts: [Post]!
+}
+
+# The Root Query for the application
+type Query {
+    recentPosts(count: Int, offset: Int): [Post]!
+}
+
+# The Root Mutation for the application
+type Mutation {
+    writePost(title: String!, text: String!, category: String, author: String!) : Post!
+}