remove running timer info when the time entry is removed

lib/stopwatch/time_entry_patch.rb

@@ -0,0 +1,18 @@
+module Stopwatch
+  module TimeEntryPatch
+    def self.apply
+      TimeEntry.prepend self unless TimeEntry < self
+    end
+
+    def self.prepended(base)
+      base.class_eval do
+        before_destroy :stop_timer
+      end
+    end
+
+    def stop_timer
+      t = Stopwatch::Timer.new(user)
+      t.update(stop: true) if t.running?
+    end
+  end
+end