remove unused column

database_schematic.pgsql

@@ -1,17 +1,18 @@
 CREATE TABLE boards (
     board_id VARCHAR(5) PRIMARY KEY,
     board_name VARCHAR(32) NOT NULL,
-    threads_ids INT8[],
     options JSON
 );
 
 CREATE TABLE threads (
-    thread_id SERIAL8 PRIMARY KEY,
+    board_id VARCHAR(5) NOT NULL,
+    thread_id BIGINT NOT NULL,
     thread_name VARCHAR(32),
     posts_ids BIGINT[],
     is_locked boolean NOT NULL,
     is_pinned boolean NOT NULL,
-    options VARCHAR(255)
+    options VARCHAR(255),
+    PRIMARY KEY(board_id, thread_id)
 );
 
 CREATE TABLE media (
@@ -19,13 +20,16 @@ CREATE TABLE media (
 );
 
 CREATE TABLE posts (
-    post_id SERIAL8 PRIMARY KEY,
+    board_id VARCHAR(5) NOT NULL,
+    thread_id BIGINT NOT NULL,
+    post_id BIGINT NOT NULL,
     options VARCHAR(255),
     content TEXT NOT NULL,
     media_ids VARCHAR(22)[],
     is_root BOOL NOT NULL,
     timestamp TIMESTAMP NOT NULL,
-    user_ip CIDR NOT NULL
+    user_ip CIDR NOT NULL,
+    PRIMARY KEY(board_id, thread_id, post_id)
 );
 
 CREATE TABLE admins (