Atualiza configuração e modelo de usuários

- Substitui application.properties por application.yaml (configuração Spring Boot em YAML)
- Adiciona entidade/modelo Users com builder
- Ajusta BackendApplication.java para refletir novas configurações/uso do modelo
- Atualiza .gitignore para ignorar diretórios e artefatos de build e dados locais
Ref.: padronização de config, preparação para persistência e melhorias de estrutura.

backend/.gitignore

@@ -35,3 +35,7 @@ out/
 
 ### VS Code ###
 .vscode/
+
+### Database ###
+data/
+

backend/src/main/java/com/hitcommunications/servermanager/BackendApplication.java

@@ -2,12 +2,19 @@ package com.hitcommunications.servermanager;
 
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
 
 @SpringBootApplication
+@RestController
 public class BackendApplication {
 
     public static void main(String[] args) {
         SpringApplication.run(BackendApplication.class, args);
     }
 
+    @GetMapping
+    public String home() {
+        return "Hello, World!";
+    }
 }

backend/src/main/java/com/hitcommunications/servermanager/model/Users.java

@@ -0,0 +1,63 @@
+package com.hitcommunications.servermanager.model;
+
+import jakarta.persistence.*;
+import lombok.*;
+import org.hibernate.annotations.CreationTimestamp;
+import org.hibernate.annotations.UpdateTimestamp;
+
+import java.sql.Timestamp;
+import java.util.UUID;
+
+@Entity
+@Table(name = "tab_users")
+@AllArgsConstructor
+@NoArgsConstructor
+@Getter
+@Setter
+@Builder
+public class Users {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.UUID)
+    @Column(updatable = false, nullable = false)
+    private UUID id;
+
+    @Column(nullable = false, unique = true)
+    private String username;
+
+    @Column(nullable = false, unique = true, length = 100)
+    private String email;
+
+    @Column(nullable = false, length = 20)
+    private String password;
+
+    @Column(nullable = false, length = 30)
+    private String firstName;
+
+    @Column(nullable = false, length = 30)
+    private String lastName;
+
+    @CreationTimestamp
+    @Column(nullable = false)
+    private Timestamp createdAt;
+
+    @UpdateTimestamp
+    @Column(nullable = false)
+    private Timestamp updatedAt;
+
+    private Timestamp lastLogin;
+
+    @PrePersist
+    private void prePersist() {
+        if (this.username == null) {
+            this.username = generateUsername();
+        }
+    }
+
+    public String generateUsername() {
+        String firstPart = this.firstName != null && this.firstName.length() >= 3 ? this.firstName.substring(0, 3) : (this.firstName != null ? this.firstName : "");
+        String secondPart = this.lastName != null && this.lastName.length() >= 3 ? this.lastName.substring(0, 3) : (this.lastName != null ? this.lastName : "");
+        this.username = firstPart + secondPart;
+        return this.username;
+    }
+}

backend/src/main/resources/application.properties

@@ -1 +0,0 @@
-spring.application.name=backend

backend/src/main/resources/application.yaml

@@ -0,0 +1,17 @@
+spring:
+  application:
+    name: backend
+  datasource:
+    url: jdbc:h2:file:./data/db
+    driver-class-name: org.h2.Driver
+    username: sa
+    password: 
+  jpa:
+    hibernate:
+      ddl-auto: update
+    database-platform: org.hibernate.dialect.H2Dialect
+  h2:
+    console:
+      enabled: true
+      path: /h2-console
+