title: How to insert multi IDs and save in database
body: <p>I'm using Laravel 7 and trying to make a automation system.<br>
  For send Letters, I have to be able to choose a few receivers.</p>
  
  <p>Here is Letter table:
  <a href="https://i.stack.imgur.com/nunR4.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/nunR4.png" alt="enter image description here"></a></p>
  
  <p>As you can see, I have <code>recieve_id</code>.<br>
  I can get IDs, but I don't know how to save IDs in my database.  </p>
  
  <p>This is my select:</p>
  
  <pre><code>&lt;select class="col-12 border mt-2 pt-2" multiple="multiple" name="recieve_id[]"&gt;
    @foreach($users as $user)
      &lt;option value="{{ $user-&gt;id }}"&gt;{{ $user-&gt;name }}&lt;/option&gt;
    @endforeach
  &lt;/select&gt;
  </code></pre>
  
  <p>This is my Controller:</p>
  
  <pre><code>Letter::create([
    'indicator_id' =&gt; $request['indicator_id'],
    'sender_id' =&gt; auth()-&gt;user()-&gt;id,
    'recieve_id' =&gt; $request['recieve_id'],
    'title' =&gt; $request['title'],
    'image' =&gt; 'default.png',
    'description' =&gt; $request['description'],
    'date' =&gt; $request['date'],
    'text' =&gt; $request['text'],
  ]);
  return redirect(route('Letter.index'));
  </code></pre>
  
  <p>Edit:</p>
  
  <p>Here is Table structure:
  <a href="https://i.stack.imgur.com/RCq14.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/RCq14.png" alt="enter image description here"></a></p>
  
  <p>Edit 2:</p>
  
  <p>Here is my destory function for letters : 
  <a href="https://i.stack.imgur.com/JrJ4p.png" rel="nofollow noreferrer">Destory Function</a></p>