How to dynamically route links in Codeigniter? - codeigniter-3

Question

I am working on a Blogging web. After creating a post, i am able to view it in the posts page. However, i have limited it to just 60 words by using the word_limitter and then there's a link Read More with the code below that should take me to a new page showing all the content of the post.
<?php echo site_url('/posts/'.$post['slug']); ?>
Now, my challenge is dynamic routing, as in, i want it in such a way that whenever i click Read More on any any post, it just opens that specific post.
My controller function
public function view($slug = NULL){
$data['post'] = $this->posts_model->get_posts($slug);
$post_id = $data['post']['id'];
$data['comments'] = $this->comments_model->get_comments($post_id);
if(empty($data['post'])){
show_404();
}
$data['title'] = $data['post']['title'];
$this->load->view('template/header');
$this->load->view('posts/readmore', $data);
$this->load->view('template/footer');
}
and my model is here
public function get_posts($slug=FALSE, $limit= FALSE, $offset =FALSE){
if($limit){
$this->db->limit($limit, $offset);
}
if($slug === FALSE){
$this->db->order_by('posts.id', 'DESC');
$this->db->join('categories', 'categories.id = posts.category_id');
$query= $this->db->get('posts');
return $query->result_array();
}
$query = $this->db->get_where('posts', array('slug' =>$slug));
return $query->row_array();
}
This is how my route looks like
$route['posts/(:any)'] = 'posts/readmore/$1';
When i click on read more, it gives me a 404. when i remove the route above and click more, it shows blank page.