Initial support for importing supplier costs

app/Models/Cost.php

@@ -0,0 +1,40 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+
+use App\Models\Cost\{Broadband,Generic,Phone};
+
+class Cost extends Model
+{
+    use HasFactory;
+
+	protected $dates = [
+		'billed_at',
+	];
+
+	/* RELATIONS */
+
+	public function broadbands()
+	{
+		return $this->hasMany(Broadband::class)
+			->where('active',TRUE);
+	}
+
+	public function generics()
+	{
+		return $this->hasMany(Generic::class)
+			->where('active',TRUE);
+	}
+
+	public function phones()
+	{
+		return $this->hasMany(Phone::class)
+			->where('active',TRUE);
+	}
+
+	/* ATTRIBUTES */
+
+}