Fix crash when deleting draft

Closes #94

Tusker/Screens/Compose/Drafts/DraftsTableViewController.swift

@@ -102,6 +102,7 @@ class DraftsTableViewController: UITableViewController {
     override func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
         guard editingStyle == .delete else { return }
         DraftsManager.shared.remove(draft(for: indexPath))
+        drafts.remove(at: indexPath.row)
         tableView.deleteRows(at: [indexPath], with: .automatic)
     }