message: create file if not present
diff: @@ -57,6 +57,6 @@ pub fn read_refpack<P: AsRef<str>>(storage_config: &StorageConfig, name: P) -> R
  }
  pub fn write_refpack<P: AsRef<str>>(storage_config: &StorageConfig, name: P, rf: &RefPack) -> Result<()> {
  - let mut file = fs::File::open(storage_config.get_refpack_filepath(name))?;
  + let mut file = fs::File::create(storage_config.get_refpack_filepath(name))?;
  rf.write(&mut file)
  }
  \ No newline at end of file
  