When i tried to create Comments to Micropost I have an error that : No route matches [POST] "/"

Please help me!!! I'm new at Rails programming. I've finished Michael Hartl's "Ruby on Tutorials" book and now I've tried to add comments to microposts but when I tried to post comments, I have an error that "No route matches [POST]".

I can't find what is wrong there?

And also I want to know that my associations is correct between models? (I want to create comments like Facebook comments to posts)

Thank you so much for your attentions.

comments_controller

class CommentsController < ApplicationController
before_action :logged_in_user, only: [:create, :destroy]
before_action :correct_user,   only: :destroy

def create
    user = User.find_by(params[:id])
    micropost = user.microposts.build(params[:micropost])

    @comment = Comment.new(params[:comment])
    @comment.micropost_id = micropost_id
    @comment.user = current_user

    if @comment.save
      flash[:success] = "Comment created!"
      redirect_to root_url
    else
      render 'static_pages/home'
    end
end
end

comment.html.erb

<h5>Comments<h5>
<div class="comment">
  <% @user.comments.each do |comment| %>
  <p><%= comment.comment %></p>
  <%= time_ago_in_words(comment.created_at) %> ago.
  <%end%>
  </div>

_comment_form.html.erb

<%= form_for :comment do |f| %>

<%= f.text_area :comment_comment, :size => "40x5", placeholder: "Comment..." %>
 <%= f.submit "Post", class: "btn btn-primary" %>
  <span class="picture">
   <%= f.file_field :picture, accept:'image/jpeg,image/gif,image/png' %>
</span>

_micropost.html.erb

<li id="micropost-<%= micropost.id %>">
<%= link_to gravatar_for(micropost.user, size: 50), micropost.user %>
<span class="user"><%= link_to micropost.user.name, micropost.user %></span>
<span class="content">
<%= micropost.content %>
<%= image_tag micropost.picture.url if micropost.picture? %>
</span>
<span class="timestamp">
 Posted <%= time_ago_in_words(micropost.created_at) %> ago.
<% if current_user?(micropost.user) %>
  <%= link_to "delete", micropost, method: :delete,
                                   data: { confirm: "You sure?" } %>
   <% end %>
    </span>
  <ol>
        <%= render "comments/comment" %>
      </ol>
      <%= render 'shared/comment_form', micropost: micropost %>
     </li>

create_comment.rb

class CreateComments < ActiveRecord::Migration
def change
create_table :comments do |t|
  t.text :comment
  t.references :user, index: true, foreign_key: true
  t.references :micropost, index: true, foreign_key: true

  t.timestamps null: false
end
add_index :comments, [:user_id, :micropost_id, :created_at]
 end
end

comment.rb

class Comment < ActiveRecord::Base
 belongs_to :user
 belongs_to :micropost
 end

micropost.rb

class Micropost < ActiveRecord::Base
  belongs_to :user
  has_many :comments
 end

user.rb

      class User < ActiveRecord::Base
      has_many :microposts, dependent: :destroy
     has_many :comments
      end

route.rb

      resources :microposts,          only: [:create, :destroy] do
       member do
      resources :comments,            only: [:create, :destroy] 
       end
     end