add coverage attributes

app/Models/Coverage.php

@@ -0,0 +1,25 @@
+<?php
+namespace App\Models;
+
+use App\Models\Dataset;
+use Illuminate\Database\Eloquent\Model;
+
+class Coverage extends Model
+{
+    protected $table = 'coverage';
+    public $timestamps = true;
+
+    protected $fillable = [
+        'elevation_min',
+        'elevation_max',
+        'elevation_absolut',
+        'depth_min',
+        'depth_max',
+        'depth_absolut'
+    ];
+
+    public function dataset()
+    {
+        return $this->belongsTo(Dataset::class, 'dataset_id', 'id');
+    }
+}