remove hardcoded addresses in Buy Button

src/App.tsx

           </div>
           <BuyButton 
             Tezos={Tezos}
+            sender={userAddress}
             FA2address="KT1BB1uMwVvJ1M3vVHXWALs1RWdgTp1rnXTR"
             receiver="tz1hJncvXvL2VyctPE685GJPXDaRJ7dtiwjm"
             amount={100}

src/components/BuyButton.tsx

 const BuyButton = ({
     Tezos,
     FA2address,
+    sender,
     receiver,
     amount
 }: {
     Tezos: TezosToolkit,
     FA2address: string,
+    sender: string,
     receiver: string,
     amount: number
 }): JSX.Element => {
 	
         const transfer_params = [
             {
-                from_: "tz1LigkX55duWS2pZt4u5qTAWUu6Sb9bMxbg",
+                from_: sender,
                 txs: [{
-                    to_: "tz1hJncvXvL2VyctPE685GJPXDaRJ7dtiwjm",
+                    to_: receiver,
                     token_id:0,
                     amount: amount
                 }]
             <button
 	className="myButton"
 	onClick={makePayment}
-	    >
-            {FA2address}
+	    >Transfer {amount}&nbsp;
+	    µ-tokens from: &nbsp;
+	    {sender}
+	    &nbsp;to:&nbsp;
+	    {receiver}
             </button>
         </div>
     );