Add pagination

app/controllers/api/v1/parks_controller.rb

@@ -1,5 +1,20 @@
 class Api::V1::ParksController < ApplicationController
+  DEFAULT_PAGE_SIZE = 10
+
   def index
-    render json: Park.all
+    parks = Park
+      .limit(per_page)
+      .offset((page - 1) * per_page)
+    render json: parks
+  end
+
+  private
+
+  def per_page
+    (params[:per_page].presence || DEFAULT_PAGE_SIZE).to_i
+  end
+
+  def page
+    (params[:page].presence || 1).to_i
   end
 end