Being able to specify a tag query parameter when fetching from an existing API using RestClient for Ruby on Rails

Question

I'm using RestClient to fetch from an external API that has a list of blog posts. I need to be able to specify the "tags" attribute so that only posts that contain that tag appear in the JSON response. For example, navigating to localhost:3000/posts?tag=tech will only show posts with tech tag.

Right now, this is what I have in my posts controller, which is static and will only give me posts with a tech tag. How do I make this dynamic so any of the tags will work with my /posts route? I know that it has something to do with specifying params in the url, but I haven't used RestClient before and could use some guidance!

class PostsController < ApplicationController
    require 'rest-client'

    def index
        url = "https:example.com/blog/posts?tag=tech"
        response = RestClient.get(url)
        render json: response, status: :ok
    end

    def ping
        render json: { success: true }, status: :ok
    end

end

Here's also my routes file for reference:

Rails.application.routes.draw do
  resources :posts

  get '/ping', to: "posts#ping"

  end