Added check for template file

Signed-off-by: kadern0 <kaderno@gmail.com>

cmd/create_github.go

@@ -7,6 +7,7 @@ import (
 	"net/url"
 	"os"
 	"os/exec"
+	"path"
 	"runtime"
 	"strings"
 	"time"
@@ -64,6 +65,10 @@ func createGitHubAppE(command *cobra.Command, _ []string) error {
 		"GitHubEvent": fmt.Sprintf("%s://system.%s/github-event", scheme, rootDomain),
 	}
 
+	if _, err := os.Stat(path.Join("./pkg/github", "index.html")); err != nil {
+		return fmt.Errorf("Cannot find the template file. You need to run this command from the root directory of the repository.\n ")
+	}
+
 	fmt.Printf("Name: %s\tRoot domain: %s\tScheme: %v\n", name, rootDomain, scheme)
 
 	launchBrowser := true