I created a Rails post form, but I can't post it (form tag) / No error occurs

Any error

This mistake, I got caught twice. The first time I didn't get an error, but for some reason I can't post! There is no error statement, so you can't even search for it! I was worried.

Why is the second time (yesterday)! I thought, but it seems that the same thing happened a few months ago ... So I was able to solve it.

Also, keep a record so that the same thing does not happen.

Specifically, the following things have occurred.

① Fill out the submission form

(2) Fill in the required items and press "Kiroku" to return to the initial screen for some reason. The URL is also strange.

What's happening

It was a simple thing. I put the form tag inside the form tag.

ruby:new.html.erb

<form>
　 <%= form_for(@post) do |f| %>
~ Abbreviation ~
   <% end %>
</form>

Nesting form elements is prohibited. I want to be careful.

Reference article

form tags cannot be nested & how to deal with them [Form tag nesting and browser interpretation](https://ja.stackoverflow.com/questions/30651/form%E3%82%BF%E3%82%B0%E3%81%AE%E5%85%A5 % E3% 82% 8C% E5% AD% 90% E3% 81% A8% E3% 83% 96% E3% 83% A9% E3% 82% A6% E3% 82% B6% E3% 83% BC% E3 % 81% AE% E8% A7% A3% E9% 87% 88)