adds finnhub market data provider

config/finnhub.php

@@ -0,0 +1,5 @@
+<?php
+
+return [
+    'key' => env('FINNHUB_API_KEY'),
+];

config/investbrain.php

@@ -6,9 +6,12 @@ return [
 
     'default' => env('MARKET_DATA_PROVIDER', 'yahoo'),
 
-    'yahoo' => App\Interfaces\MarketData\YahooMarketData::class,
-    'alphavantage' => App\Interfaces\MarketData\AlphaVantageMarketData::class,
-    'fake' => App\Interfaces\MarketData\FakeMarketData::class,
+    'interfaces' => [
+        'yahoo' => App\Interfaces\MarketData\YahooMarketData::class,
+        'alphavantage' => App\Interfaces\MarketData\AlphaVantageMarketData::class,
+        'finnhub' => App\Interfaces\MarketData\FinnhubMarketData::class,
+        'fake' => App\Interfaces\MarketData\FakeMarketData::class,
+    ],
 
     'self_hosted' => env('SELF_HOSTED', true)
 ];