refactor: rename src folder with app

app/routes.cr

@@ -0,0 +1,23 @@
+require "./controllers/**"
+
+module App
+  before_all do |env|
+    env.response.content_type = "application/json"
+  end
+
+  get "/api/ping" do |env|
+    Controllers::Ping::Get.new.call(env)
+  end
+
+  get "/:slug" do |env|
+    Controllers::Link::Index.new.call(env)
+  end
+
+  get "/api/links/:id" do |env|
+    Controllers::Link::Get.new.call(env)
+  end
+
+  post "/api/links" do |env|
+    Controllers::Link::Create.new.call(env)
+  end
+end