Revert "This shouldn't have been here"

This reverts commit 02922b9.

src/Command.php

@@ -0,0 +1,18 @@
+<?php
+
+namespace craft\fixfks;
+
+use craft\helpers\MigrationHelper;
+
+class Command extends \craft\db\Command
+{
+    public function addForeignKey($name, $table, $columns, $refTable, $refColumns, $delete = null, $update = null)
+    {
+        // Only add it if it doesn't exist yet
+        if (!MigrationHelper::doesForeignKeyExist($table, $columns)) {
+            return parent::addForeignKey($name, $table, $columns, $refTable, $refColumns, $delete, $update);
+        }
+
+        return $this;
+    }
+}