edited ChannelQuerySet to include self enrollments filter, issue: subscribe button is connected to post slug instead of channel slug since ChannelDetailView takes on the model Post with context post_list instead of Channel
added some tests
subscribe button now subscribes to channel instead of post. No actual subscription functionality yet, but instead of the post slug, it is now taking on the channel slug.
 removed notes to self
 subscribing works, but there is a bug where when the follower is added, it creates another channel
 added .distinct() to queryset to fix duplicate channel problem
 added distinct() to posts too. to do next: finish writing test cases
made another queryset method to filter out posts on ChannelDetailView based on subscribed or not, but it makes it more complex. to do: use existing check of whether user is a follower to accomplish the same task. Also to do: write more tests.