Feat: Adds multi currency support to API (#90)

app/Http/Resources/HoldingResource.php

@@ -21,6 +21,7 @@ class HoldingResource extends JsonResource
             'portfolio_id' => $this->portfolio_id,
             'symbol' => $this->symbol,
             'quantity' => $this->quantity,
+            'currency' => $this->market_data->currency,
             'reinvest_dividends' => $this->reinvest_dividends,
             'average_cost_basis' => $this->average_cost_basis,
             'total_cost_basis' => $this->total_cost_basis,

app/Http/Resources/TransactionResource.php

@@ -22,6 +22,7 @@ class TransactionResource extends JsonResource
             'portfolio_id' => $this->portfolio_id,
             'transaction_type' => $this->transaction_type,
             'quantity' => $this->quantity,
+            'currency' => $this->market_data->currency,
             'cost_basis' => $this->cost_basis,
             'sale_price' => $this->sale_price,
             'split' => $this->split,

app/Http/Resources/UserResource.php

@@ -22,6 +22,10 @@ class UserResource extends JsonResource
             'name' => $this->name,
             'email' => $this->email,
             'profile_photo_url' => $this->profile_photo_url,
+            'options' => [
+                'display_currency' => $this->getCurrency(),
+                'locale' => $this->getLocale(),
+            ],
             'created_at' => $this->created_at,
             'updated_at' => $this->updated_at,
         ];