First of all, this is not specific to iOS.
You must decide whether you want to lazily load AddPostPage.
If so, take all mentions of it out of app.module.ts and make all references to it in calls to the navigation system be strings: nav.push("AddPostPage") not nav.push(AddPostPage).
If not, leave it in app.module.ts, delete add-post-page.module.ts, take the IonicPage decorator off of the AddPostPage component, and make all references in calls to the navigation system constructors: the opposite of above.
Finally, in my personal opinion the generators cause more hassle than they generate value, so I just don’t use them at all.