Add fluentd-ui gem updates check

app/workers/fluentd_ui_update_check.rb

@@ -0,0 +1,15 @@
+class FluentdUiUpdateCheck
+  include SuckerPunch::Job
+
+  def perform
+    pl = Plugin.new(gem_name: "fluentd-ui")
+    if pl.gem_versions # NOTE: fluentd-ui is not released yet, so `pl.latest_version` will fail for now
+      FluentdUI.latest_version = pl.latest_version
+    end
+    later(3600) # will be checked every hour
+  end
+
+  def later(sec)
+    after(sec) { perform }
+  end
+end

lib/fluentd-ui.rb

@@ -1,2 +1,12 @@
 module FluentdUI
+  def self.latest_version=(version)
+    @latest = version
+  end
+
+  def self.update_available?
+    return unless @latest
+    latest = Gem::Version.new(@latest)
+    current = Gem::Version.new(::FluentdUI::VERSION)
+    latest > current
+  end
 end