feat: add reciprocal user blocking

app/Models/UserBlock.php

@@ -0,0 +1,28 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+class UserBlock extends Model
+{
+    /** @use HasFactory<\Database\Factories\UserBlockFactory> */
+    use HasFactory;
+
+    protected $fillable = [
+        'blocker_id',
+        'blocked_id',
+    ];
+
+    public function blocker(): BelongsTo
+    {
+        return $this->belongsTo(User::class, 'blocker_id');
+    }
+
+    public function blocked(): BelongsTo
+    {
+        return $this->belongsTo(User::class, 'blocked_id');
+    }
+}