Append Data to First Empty Row

function appendData() {

  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var source = ss.getRange("rejoin!A2:E51");
  var destSheet = ss.getSheetByName("cache");
  destSheet.appendRow(source.getValues()[0]);
  destSheet.appendRow(source.getValues()[0]);
  destSheet.appendRow(source.getValues()[0]);
  destSheet.appendRow(source.getValues()[0]);
  destSheet.appendRow(source.getValues()[0]);
  destSheet.appendRow(source.getValues()[0]);
  destSheet.appendRow(source.getValues()[0]);

}