fix: resolve self-referencing FK constraint error in abac_chains migration

Author: somethim

composer.json

@@ -1,7 +1,7 @@
 {
     "name": "zennit/abac",
     "description": "Attribute-Based Access Control (ABAC) for Laravel",
-    "version": "2.0.2",
+    "version": "2.0.3",
     "type": "library",
     "license": "MIT",
     "keywords": [

database/migrations/create_abac_tables.php

@@ -41,10 +41,14 @@ public function up(): void
             $table->uuid('_id')->primary();
             $table->timestamps();
             $table->enum('operator', LogicalOperators::values());
-            $table->foreignUuid('_chain')->nullable()->constrained('abac_chains', '_id')->cascadeOnDelete();
+            $table->uuid('_chain')->nullable();
             $table->foreignUuid('_policy')->unique()->nullable()->constrained('abac_policies', '_id')->cascadeOnDelete();
         });
 
+        Schema::table('abac_chains', function (Blueprint $table) {
+            $table->foreign('_chain')->references('_id')->on('abac_chains')->cascadeOnDelete();
+        });
+
         Schema::create('abac_checks', function (Blueprint $table) {
             $table->uuid('_id')->primary();
             $table->timestamps();