Add basic server side form validation

src/main/java/polish_community_group_11/polish_community/event/models/EventForm.java

@@ -2,6 +2,7 @@ package polish_community_group_11.polish_community.event.models;
 
 import jakarta.validation.constraints.FutureOrPresent;
 import jakarta.validation.constraints.NotEmpty;
+import jakarta.validation.constraints.NotNull;
 import jakarta.validation.constraints.Pattern;
 import lombok.AllArgsConstructor;
 import lombok.Data;
@@ -15,19 +16,22 @@ import java.time.LocalTime;
 @NoArgsConstructor
 @AllArgsConstructor
 public class EventForm {
+
     private int event_id;
     @NotEmpty(message = "Please provide event title")
     private String event_title;
     @NotEmpty(message = "Please provide event description")
     private String description;
     @FutureOrPresent(message = "The date cannot be in the past.")
+    @NotNull(message = "Date is required.")
     private LocalDate event_date;
+    @NotNull(message = "Time is required.")
     private LocalTime event_time;
     @NotEmpty(message = "Please provide a location")
     private String location;
     private int user_id;
     @NotEmpty(message = "Please provide event image url")
-    @Pattern(regexp = "https?://.*\\.(png|jpg|jpeg|gif)", message = "Must be a valid image URL (png, jpg, jpeg, gif).")
+    @Pattern(regexp = "https?://.*.(png|jpg|jpeg|gif)", message = "Must be a valid image URL (png, jpg, jpeg, gif).")
     private String imageUrl;
     private String whyJoin;
     private String benefits;