Maybe memory leaks

[mengxiangjian]

Hi. I found this good repo today, and learn so much from it. But I maybe just found a memory leak.
Select the "Network" tab, and select one post what ever you like, then the edit post vc come in, then click the back button, edit post vc out. Now, check the memory graph in Xcode, the edit post vc instance can't be released. I check the code and don't know why.

I think memory leak is a difficult thing in software develop work, especially when using RxSwift. Hope you can correct this.