Day selection stops working when re-selecting weekly option in custom schedule

[rachdaup93]

There is an issue that happens when creating a custom weekly schedule. The days of the week are not selectable if you initially select weekly, then switch to another frequency, then reselect weekly.

Steps:

1. Select Custom schedule ... in the recurring rule drop-down.
2. Choose Weekly for the frequency
3. Change from Weekly to any other frequency (i.e. Daily)
4. Change back to Weekly frequency

The days of the week will not highlight when being selected.

[glaszig]

i came across this issue in my fork and fixed it. see #166.

Gemfile:

gem "recurring_select", github: "glaszig/recurring_select", branch: "modernization"