Merge branch 'upcoming' into 'master'

Implements upcoming filter in milstones

![Imgur](http://i.imgur.com/Oc2LZrF.png)

@DouweM @JobV I think this is what you wanted :) Lemme know if it there is something that need changing
Had alot of fun doing it!

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/14102

See merge request !3148

CHANGELOG

@@ -36,6 +36,7 @@ v 8.5.5
   - Prevent a 500 error in Todos when author was removed
   - Fix pagination for filtered dashboard and explore pages
   - Fix "Show all" link behavior
+  - Add #upcoming filter to Milestone filter (Tiago Botelho)
 
 v 8.5.4
   - Do not cache requests for badges (including builds badge)

app/finders/issuable_finder.rb

@@ -244,10 +244,17 @@ class IssuableFinder
     items
   end
 
+  def filter_by_upcoming_milestone?
+    params[:milestone_title] == '#upcoming'
+  end
+
   def by_milestone(items)
     if milestones?
       if filter_by_no_milestone?
         items = items.where(milestone_id: [-1, nil])
+      elsif filter_by_upcoming_milestone?
+        upcoming = Milestone.where(project_id: projects).upcoming
+        items = items.joins(:milestone).where(milestones: { title: upcoming.title })
       else
         items = items.joins(:milestone).where(milestones: { title: params[:milestone_title] })
 

app/helpers/milestones_helper.rb

@@ -59,6 +59,7 @@ module MilestonesHelper
     grouped_milestones = grouped_milestones.sort_by { |x| x.due_date.nil? ? epoch : x.due_date }
     grouped_milestones.unshift(Milestone::None)
     grouped_milestones.unshift(Milestone::Any)
+    grouped_milestones.unshift(Milestone::Upcoming)
 
     options_from_collection_for_select(grouped_milestones, 'name', 'title', params[:milestone_title])
   end

app/models/milestone.rb

@@ -19,6 +19,7 @@ class Milestone < ActiveRecord::Base
   MilestoneStruct = Struct.new(:title, :name, :id)
   None = MilestoneStruct.new('No Milestone', 'No Milestone', 0)
   Any = MilestoneStruct.new('Any Milestone', '', -1)
+  Upcoming = MilestoneStruct.new('Upcoming', '#upcoming', -2)
 
   include InternalId
   include Sortable
@@ -81,6 +82,10 @@ class Milestone < ActiveRecord::Base
     super("milestones", /(?<milestone>\d+)/)
   end
 
+  def self.upcoming
+    self.where('due_date > ?', Time.now).order(due_date: :asc).first
+  end
+
   def to_reference(from_project = nil)
     escaped_title = self.title.gsub("]", "\\]")