refactor poll and lottery forms, add poll notifications

backend/src/main/java/com/openisle/model/NotificationType.java

@@ -40,6 +40,12 @@ public enum NotificationType {
     LOTTERY_WIN,
     /** Your lottery post was drawn */
     LOTTERY_DRAW,
+    /** Someone participated in your poll */
+    POLL_VOTE,
+    /** Your poll post has concluded */
+    POLL_RESULT_OWNER,
+    /** A poll you participated in has concluded */
+    POLL_RESULT_PARTICIPANT,
     /** Your post was featured */
     POST_FEATURED,
     /** You were mentioned in a post or comment */

backend/src/main/java/com/openisle/model/PollPost.java

@@ -15,10 +15,6 @@ import java.util.*;
 @NoArgsConstructor
 @PrimaryKeyJoinColumn(name = "post_id")
 public class PollPost extends Post {
-
-    @Column(nullable = false)
-    private String question;
-
     @ElementCollection
     @CollectionTable(name = "poll_post_options", joinColumns = @JoinColumn(name = "post_id"))
     @Column(name = "option_text")
@@ -38,4 +34,7 @@ public class PollPost extends Post {
 
     @Column
     private LocalDateTime endTime;
+
+    @Column
+    private boolean resultAnnounced = false;
 }