build out cli and add size and gather functionality

source/source.go

@@ -18,11 +18,12 @@ import (
 // - file hash
 // - modified date
 
-func GatherInfo(path string, db db.DB) {
+func GatherInfo(path string, db db.DB) error {
 	err := walkDir(path, db)
 	if err != nil {
-		log.Fatal(err)
+		return fmt.Errorf("error walking directory: %w", err)
 	}
+	return nil
 }
 
 func walkDir(dirPath string, db db.DB) error {