Fixed invalid constraint for comments table in sqlite and mysql schema

common.php

@@ -6,7 +6,7 @@ require __DIR__.'/core/translator.php';
 
 $registry = new Core\Registry;
 
-$registry->db_version = 10;
+$registry->db_version = 11;
 
 $registry->db = function() use ($registry) {
     require __DIR__.'/vendor/PicoDb/Database.php';

schemas/mysql.php

@@ -2,6 +2,10 @@
 
 namespace Schema;
 
+function version_11($pdo)
+{
+}
+
 function version_10($pdo)
 {
 }
@@ -125,7 +129,7 @@ function version_1($pdo)
             comment TEXT,
             PRIMARY KEY (id),
             FOREIGN KEY(task_id) REFERENCES tasks(id) ON DELETE CASCADE,
-            FOREIGN KEY(user_id) REFERENCES tasks(id) ON DELETE CASCADE
+            FOREIGN KEY(user_id) REFERENCES users(id) ON DELETE CASCADE
         ) ENGINE=InnoDB CHARSET=utf8
     ");
 

schemas/sqlite.php

@@ -2,6 +2,33 @@
 
 namespace Schema;
 
+function version_11($pdo)
+{
+    $pdo->exec(
+        'ALTER TABLE comments RENAME TO comments_bak'
+    );
+
+    $pdo->exec(
+        'CREATE TABLE comments (
+            id INTEGER PRIMARY KEY,
+            task_id INTEGER,
+            user_id INTEGER,
+            date INTEGER,
+            comment TEXT,
+            FOREIGN KEY(task_id) REFERENCES tasks(id) ON DELETE CASCADE,
+            FOREIGN KEY(user_id) REFERENCES users(id) ON DELETE CASCADE
+        )'
+    );
+
+    $pdo->exec(
+        'INSERT INTO comments SELECT * FROM comments_bak'
+    );
+
+    $pdo->exec(
+        'DROP TABLE comments_bak'
+    );
+}
+
 function version_10($pdo)
 {
     $pdo->exec(