Undefined method `errors' for nil:NilClass - Ruby tutorial - ruby-on-rails

Question

I've been looking for the same problem but not found it.
I'm following this guide, and I'm stuck on setting validations for the text field.
Model (article.rb):
class Article < ActiveRecord::Base
validates :title, presence: true, length: { minimum: 5 }
end
Controller:
class ArticlesController < ApplicationController:
def new
#article = Article.new
end
def create
#article = Article.new(article_params)
if #article.save
redirect_to #article
else
render 'new'
end
end
private
def article_params
params.require(:article).permit(:title, :text)
end
View (new.html.erb):
<%= form_for :article, url: articles_path do |f| %>
<% if #article.errors.any? %>
<div id="error_explanation">
<h2>
<%= pluralize(#article.errors.count, "error") %> prohibited this article from being saved:
</h2>
<ul>
<% #article.errors.full_messages.each do |msg| %>
<li><%= msg %></li>
<% end %>
</ul>
</div>
<% end %>
<p>
<%= f.label :title %><br>
<%= f.text_field :title %>
</p>
<p>
<%= f.label :text %><br>
<%= f.text_area :text %>
</p>
<p>
<%= f.submit %>
</p>
<% end %>
<%= link_to 'Back', articles_path %>
And when I try to add a new article I open http://localhost:3000/articles/new but instead of the form I see error undefined method errors' for nil:NilClass because of the error in this line <% if #article.errors.any? %>
What am I missing here. Looks like #article is being validated before created? How can I fix it?
index.html.erb:
<h1>Listing articles</h1>
<%= link_to "New article", new_article_path %>
<table>
<tr>
<th>Title</th>
<th>Text</th>
</tr>
<% #articles.each do |article| %>
<tr>
<td><%= article.title %></td>
<td><%= article.text %></td>
</tr>
<% end %>
</table>

Answer 1

You need to call:
<%= form_for #article, url: articles_path do |f| %>
In the first line of new.html.erb

Answer 2

Change the form_for to
<%= form_for(#article) do |f| %>
<% if #article.errors.any? %>
<div id="error_explanation">
<h2>
<%= pluralize(#article.errors.count, "error") %> prohibited
this article from being saved:
</h2>
<ul>
<% #article.errors.full_messages.each do |msg| %>
<li><%= msg %></li>
<% end %>
</ul>
</div>
<% end %>
........
<% end %>
articles_controller.rb
class ArticlesController < ApplicationController
....
end