Small refactor.

app/models/concerns/issuable.rb

@@ -38,7 +38,6 @@ module Issuable
     has_many :label_links, as: :target, dependent: :destroy
     has_many :labels, through: :label_links
     has_many :todos, as: :target, dependent: :destroy
-    has_many :timelogs, as: :trackable, dependent: :destroy
 
     has_one :metrics
 

app/models/concerns/time_trackable.rb

@@ -12,6 +12,8 @@ module TimeTrackable
     attr_reader :time_spent
 
     alias_method :time_spent?, :time_spent
+
+    has_many :timelogs, as: :trackable, dependent: :destroy
   end
 
   def spend_time=(args)
@@ -32,7 +34,7 @@ module TimeTrackable
   private
 
   def valid_spend_time_args?(args)
-    return false unless [:seconds, :user].all? { |k| args.key?(k) }
+    return false if [:seconds, :user].any? { |k| args[k].blank? }
 
     # time to subtract exceeds the total time spent
     seconds = args[:seconds]