title: Add parameters to post request with Rest-client rails
body: <p>I need to make a Post request using Rest-Client in my rails backend. I can successfully do it by the following: <code>rv = RestClient.post URL, id.to_json, :content_type =&gt; 'application/json'</code></p>
  
  <p>I need to add a tag parameter but can't make it work. I've tried different combinations of the following: <code>rv = RestClient.post URL, {:params =&gt; {:tag =&gt; 'TAG'}}, id.to_json, :content_type =&gt; 'application/json'</code> and receive errors about syntax (wrong number of arguments). The params would go on the url, the id.to_json would be part of the body. I can't find documentation that talks about this specific use case.</p>