Add NPS client class

app/lib/nps_client.rb

@@ -0,0 +1,21 @@
+class NpsClient
+  def self.current
+    @current ||= new
+  end
+
+  def parks(offset: 0)
+    conn.get('parks', { start: offset })
+  end
+
+  private
+
+  def conn
+    @conn ||= Faraday.new(
+      url: 'https://developer.nps.gov/api/v1',
+      headers: { 'X-Api-Key': ENV.fetch('NPS_API_KEY') }
+    ) do |builder|
+      builder.response :json
+      builder.response :raise_error
+    end
+  end
+end