Ensure authentication token is set (#28)

* Ensure authentication token is set

* Don't panic

Author: ilayaraja89

main.go

@@ -17,6 +17,12 @@ import (
 )
 
 func main() {
+	// Assert authentication
+	authToken, ok := os.LookupEnv("LEDGER_AUTH_TOKEN")
+	if !ok || authToken == "" {
+		log.Fatal("Cannot start the server. Authentication token is not set!!")
+	}
+
 	db, err := sql.Open("postgres", os.Getenv("DATABASE_URL"))
 	if err != nil {
 		log.Panic("Unable to connect to Database:", err)