use spring boot autowired for service injection

src/main/java/wtf/beatrice/releasehive/resource/AccountResource.java

@@ -1,17 +1,20 @@
 package wtf.beatrice.releasehive.resource;
 
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.web.bind.annotation.*;
 import wtf.beatrice.releasehive.util.JsonUtil;
 import wtf.beatrice.releasehive.model.User;
 import wtf.beatrice.releasehive.service.AccountService;
 
-import java.util.UUID;
-
 @RequestMapping("/api/v1/users")
 @RestController
 public class AccountResource {
 
-    private final AccountService accountService = new AccountService();
+    private final AccountService accountService;
+    
+    public AccountResource(@Autowired AccountService accountService) {
+        this.accountService = accountService;
+    }
 
 
     @PostMapping(

src/main/java/wtf/beatrice/releasehive/service/AccountService.java

@@ -1,17 +1,9 @@
 package wtf.beatrice.releasehive.service;
 
-import org.hibernate.Session;
-import org.hibernate.Transaction;
-import wtf.beatrice.releasehive.db.HibernateManager;
 import wtf.beatrice.releasehive.model.User;
 
-public class AccountService
+public interface AccountService
 {
 
-    public void registerUser(User user) {
-        Session session = HibernateManager.getSession();
-        Transaction transaction = session.beginTransaction();
-        session.save(user);
-        transaction.commit();
-    }
+    void registerUser(User user);
 }

src/main/java/wtf/beatrice/releasehive/service/AccountServiceImpl.java

@@ -0,0 +1,19 @@
+package wtf.beatrice.releasehive.service;
+
+import org.hibernate.Session;
+import org.hibernate.Transaction;
+import org.springframework.stereotype.Service;
+import wtf.beatrice.releasehive.db.HibernateManager;
+import wtf.beatrice.releasehive.model.User;
+
+@Service
+public class AccountServiceImpl implements AccountService {
+
+    @Override
+    public void registerUser(User user) {
+        Session session = HibernateManager.getSession();
+        Transaction transaction = session.beginTransaction();
+        session.save(user);
+        transaction.commit();
+    }
+}