Changing drip dates for already dripped content.

[RiaanKnoetze]

Link to ticket: https://woothemes.zendesk.com/agent/tickets/368952

When changing dates for drip content, existing users that already had access to content is now no longer able to access their content as the drip date is in the future.

@danjjohnson mentioned:

To do it without affecting them, we would need to save a drip status for each user, so once the lesson has dripped for them, it will remain accessible even if the lesson drip date is changed.

@dwainm Would love to get your insight on this.

[danjjohnson]

@RiaanKnoetze just found that there is already an open issue about this: #48

Closing this one as a duplicate.