Add seed parks service

app/services/seed/parks.rb

@@ -0,0 +1,21 @@
+class Seed::Parks
+  def self.call(...)
+    new(...).call
+  end
+
+  def call
+    offset, total = 0, 1
+    while offset < total do
+      response_body = NpsClient.current.parks(offset: offset).body
+      offset = response_body['start'].to_i + response_body['limit'].to_i
+      total = response_body['total'].to_i
+      parks = response_body['data']
+        .pluck('parkCode', 'name', 'states')
+        .map do |code, name, states|
+          { code:, name:, states: }
+        end
+      Park.upsert_all(parks, unique_by: :code)
+      Rails.logger.info("Upserted #{parks.count} national parks")
+    end
+  end
+end