Fix #1000 - Update record when a user leaves the study

[cagryInside]

This is a WIP PR, please do not merge.

This PR updates the spreadsheet when a travel-behavior study participant opt-outs from the study.

@barbeau Before merging this PR, could you please create a new Google script app and deploy the following code as a web application? The permissions should be the same as the one for registration app. Also, could you please update the GOOGLE_DOC_ID with the OneBusAway Travel Behavior Data - Email mapping file's id; I just didn't put it here because of the privacy concerns. Once you deploy the app, please let me know with the URL; like that I can update the PR.

Thanks a lot.

function doGet(e) {
  var GOOGLE_DOC_ID = "";

  var ss = SpreadsheetApp.openById(GOOGLE_DOC_ID);
  var sheet = ss.getSheets()[0];
  var d = new Date();
  var date = Utilities.formatDate(d, "GMT", "MM/dd/yyyy hh:mm:ss a");
  var dateIso = Utilities.formatDate(d, "GMT", "yyyy-MM-dd'T'HH:mm:ss'Z'");
  
  var id = e.parameter.id;

  var row = findRowById(sheet, id);
  
  // Couldn't find the id in the spreadsheet
  if (row == -1) {
      return ContentService.createTextOutput("Couldn't find Id").setMimeType(ContentService.MimeType.TEXT);
  }

  sheet.getRange(row,5).setValue(date);
  sheet.getRange(row,6).setValue(dateIso);
  return ContentService.createTextOutput("STATUS OK").setMimeType(ContentService.MimeType.TEXT);
}


function findRowById(sheet, id) {
  var row = 1;
  while (true) {
    var val = sheet.getRange(row, 1).getValue();
    if (val == id) return row;
    if (val == "") return -1;
    row++;
  }
}

[barbeau]

@cagryInside I went ahead and updated the PR with the new URL. Thanks!