View errors when calling methods on deleted user of the post

[vrtsev]

Case:

1. Login

Bug: News feed page throws error 'Undefined method for nil class'
File location: 'app/views/news_feed/_posts.html.erb'
Code fragments:
image_tag(post.user.photo_url, class: 'img-circle w-32 m-r pull-left') if post.user
link_to post.title, (post.user ? user_post_path(post.user.id, post) : '#' )
post.user ? post.user.name : 'Удален'

Expected: There is a 'placeholder user' with name 'Deleted' which will be displayed insted real deleted user. You should implement decorators or use 'gem Cells' which will give you ability to setup logic for view templates of application