added currency transformer to incomes/expenses api

app/Models/Expense/BillPayment.php

@@ -27,6 +27,11 @@ class BillPayment extends Model
         return $this->belongsTo('App\Models\Banking\Account');
     }
 
+    public function currency()
+    {
+        return $this->belongsTo('App\Models\Setting\Currency', 'currency_code', 'code');
+    }
+
     public function bill()
     {
         return $this->belongsTo('App\Models\Expense\Bill');

app/Models/Income/InvoicePayment.php

@@ -27,6 +27,11 @@ class InvoicePayment extends Model
         return $this->belongsTo('App\Models\Banking\Account');
     }
 
+    public function currency()
+    {
+        return $this->belongsTo('App\Models\Setting\Currency', 'currency_code', 'code');
+    }
+
     public function invoice()
     {
         return $this->belongsTo('App\Models\Income\Invoice');

app/Models/Setting/Currency.php

@@ -38,6 +38,11 @@ class Currency extends Model
         return $this->hasMany('App\Models\Income\Invoice', 'currency_code', 'code');
     }
 
+    public function invoice_payments()
+    {
+        return $this->hasMany('App\Models\Income\InvoicePayment', 'currency_code', 'code');
+    }
+
     public function revenues()
     {
         return $this->hasMany('App\Models\Income\Revenue', 'currency_code', 'code');
@@ -48,6 +53,11 @@ class Currency extends Model
         return $this->hasMany('App\Models\Expense\Bill', 'currency_code', 'code');
     }
 
+    public function bill_payments()
+    {
+        return $this->hasMany('App\Models\Expense\BillPayment', 'currency_code', 'code');
+    }
+
     public function payments()
     {
         return $this->hasMany('App\Models\Expense\Payment', 'currency_code', 'code');