Added Quote interface

src/interface/quote.ts

@@ -1,5 +1,22 @@
 export class Quote {
-    
+    readonly companyName: string;
+
+    readonly earningsPerShare: number;
+    readonly estimatedEarnings: number;
+
+    readonly lastTrade: number;
+
+    readonly symbol: string;
+
+    constructor(companyName: string, earningsPerShare: number, estimatedEarnings: number, lastTrade: number, symbol: string) {
+        this.companyName = companyName;
+        this.earningsPerShare = earningsPerShare;
+        this.estimatedEarnings = estimatedEarnings;
+        this.lastTrade = lastTrade;
+        this.symbol = symbol;
+    }
 }
 
-
+export interface QuoteProvider {
+    readonly fetchQuote: (symbol: string) => Promise<Quote>;
+}