Allow SIGIL_CWD for add

main.go

@@ -110,7 +110,14 @@ func addCmd(args []string) error {
 		return errors.New("missing path")
 	}
 
-	absPath, err := filepath.Abs(args[0])
+	argPath := args[0]
+	if !filepath.IsAbs(argPath) {
+		if cwd := os.Getenv("SIGIL_CWD"); cwd != "" {
+			argPath = filepath.Join(cwd, argPath)
+		}
+	}
+
+	absPath, err := filepath.Abs(argPath)
 	if err != nil {
 		return err
 	}