Update CreateAt and UpdateAt to use @CreationTimestamp and @UpdateTimestamp annotations respectively

.env.example

@@ -1,4 +1,5 @@
 # Database section
+DB_URL=     # JDBC URL
 DB_USER=
 DB_PASSWORD=
 

server/src/main/java/com/mixel/docusphere/entity/Document.java

@@ -1,6 +1,9 @@
 package com.mixel.docusphere.entity;
 
 import jakarta.persistence.*;
+import org.hibernate.annotations.CreationTimestamp;
+import org.hibernate.annotations.UpdateTimestamp;
+
 import java.util.UUID;
 import java.time.LocalDateTime;
 
@@ -25,9 +28,11 @@ public class Document {
     @JoinColumn(name = "UserID", nullable = false)
     private User user;
 
+    @CreationTimestamp
     @Column(name = "CreatedAt", nullable = false, updatable = false)
     private LocalDateTime createdAt;
 
+    @UpdateTimestamp
     @Column(name = "UpdatedAt", nullable = false)
     private LocalDateTime updatedAt;
 

server/src/main/java/com/mixel/docusphere/entity/User.java

@@ -2,6 +2,9 @@ package com.mixel.docusphere.entity;
 
 import com.fasterxml.jackson.annotation.JsonIgnore;
 import jakarta.persistence.*;
+import org.hibernate.annotations.CreationTimestamp;
+import org.hibernate.annotations.UpdateTimestamp;
+
 import java.time.LocalDateTime;
 import java.util.UUID;
 
@@ -30,9 +33,11 @@ public class User {
     @Column(name = "PasswordSalt", nullable = false)
     private String passwordSalt;
 
+    @CreationTimestamp
     @Column(name = "CreatedAt", nullable = false, updatable = false)
     private LocalDateTime createdAt;
 
+    @UpdateTimestamp
     @Column(name = "UpdatedAt", nullable = false)
     private LocalDateTime updatedAt;