Fix Invoice/Estimate template issues and Add Payment Receipt, Custom Payment Modes and Item units

app/Unit.php

@@ -0,0 +1,26 @@
+<?php
+
+namespace Crater;
+
+use Illuminate\Database\Eloquent\Model;
+use Crater\Item;
+
+class Unit extends Model
+{
+    protected $fillable = ['name', 'company_id'];
+
+    public function items()
+    {
+        return $this->hasMany(Item::class);
+    }
+
+    public function company()
+    {
+        return $this->belongsTo(Company::class);
+    }
+
+    public function scopeWhereCompany($query, $company_id)
+    {
+        $query->where('company_id', $company_id);
+    }
+}