pttodo-cli works even if file does not initially exist

cmd/pttodo-cli/cli.go

@@ -40,14 +40,16 @@ func edit(filepath string) error {
 		if err != nil {
 			return err
 		}
-		g, err := os.Open(filepath)
-		if err != nil {
-			return err
+		if _, err := os.Stat(filepath); err == nil {
+			g, err := os.Open(filepath)
+			if err != nil {
+				return err
+			}
+			if _, err := io.Copy(f, g); err != nil {
+				return err
+			}
+			g.Close()
 		}
-		if _, err := io.Copy(f, g); err != nil {
-			return err
-		}
-		g.Close()
 		f.Close()
 		tempFile = f.Name()
 		return nil