Add a "populate metrics directly" option to the cycle analytics seed.

- The normal seed creates all the data for cycle analytics the "right"
  way. It creates issues, merge requests, commits, branches,
  deployments, etc. This is good, but too slow for perf testing.
  Generating a 1000 sets of records this way takes more than an hour.

- When the `CYCLE_ANALYTICS_POPULATE_METRICS_DIRECTLY` environment
  variable is passed in, the seed only creates issues and merge
  requests. It then adds the `metrics` for each issue and
  merge request directly, to save time.

- The seed now takes about 4 minutes to run for 1000 sets of records.

db/fixtures/development/17_cycle_analytics.rb

 require 'sidekiq/testing'
+require './spec/support/test_env'
 
 class Gitlab::Seeder::CycleAnalytics
   def initialize(project, perf: false)
@@ -21,10 +22,64 @@ class Gitlab::Seeder::CycleAnalytics
     end
   end
 
+  def seed_metrics!
+    @issue_count.times do |index|
+      # Issue
+      Timecop.travel 5.days.from_now
+      title = "#{FFaker::Product.brand}-#{FFaker::Product.brand}-#{rand(1000)}"
+      issue = Issue.create(project: @project, title: title, author: @user)
+      issue_metrics = issue.metrics
+
+      # Milestones / Labels
+      Timecop.travel 5.days.from_now
+      if index.even?
+        issue_metrics.first_associated_with_milestone_at = rand(6..12).hours.from_now
+      else
+        issue_metrics.first_added_to_board_at = rand(6..12).hours.from_now
+      end
+
+      # Commit
+      Timecop.travel 5.days.from_now
+      issue_metrics.first_mentioned_in_commit_at = rand(6..12).hours.from_now
+
+      # MR
+      Timecop.travel 5.days.from_now
+      branch_name = "#{FFaker::Product.brand}-#{FFaker::Product.brand}-#{rand(1000)}"
+      @project.repository.add_branch(@user, branch_name, 'master')
+      merge_request = MergeRequest.create(target_project: @project, source_project: @project, source_branch: branch_name, target_branch: 'master', title: branch_name, author: @user)
+      merge_request_metrics = merge_request.metrics
+
+      # MR closing issues
+      Timecop.travel 5.days.from_now
+      MergeRequestsClosingIssues.create!(issue: issue, merge_request: merge_request)
+
+      # Merge
+      Timecop.travel 5.days.from_now
+      merge_request_metrics.merged_at = rand(6..12).hours.from_now
+
+      # Start build
+      Timecop.travel 5.days.from_now
+      merge_request_metrics.latest_build_started_at = rand(6..12).hours.from_now
+
+      # Finish build
+      Timecop.travel 5.days.from_now
+      merge_request_metrics.latest_build_finished_at = rand(6..12).hours.from_now
+
+      # Deploy to production
+      Timecop.travel 5.days.from_now
+      merge_request_metrics.first_deployed_to_production_at = rand(6..12).hours.from_now
+
+      issue_metrics.save!
+      merge_request_metrics.save!
+
+      print '.'
+    end
+  end
+
   def seed!
     Sidekiq::Testing.inline! do
-      issues = create_issues(@project)
-      print '.'
+      issues = create_issues
+      puts '.'
 
       # Stage 1
       Timecop.travel 5.days.from_now
@@ -62,7 +117,7 @@ class Gitlab::Seeder::CycleAnalytics
 
   private
 
-  def create_issues(project)
+  def create_issues
     Array.new(@issue_count) do
       issue_params = {
         title: "Cycle Analytics: #{FFaker::Lorem.sentence(6)}",
@@ -182,6 +237,9 @@ Gitlab::Seeder.quiet do
   elsif ENV['CYCLE_ANALYTICS_PERF_TEST']
     seeder = Gitlab::Seeder::CycleAnalytics.new(Project.order(:id).first, perf: true)
     seeder.seed!
+  elsif ENV['CYCLE_ANALYTICS_POPULATE_METRICS_DIRECTLY']
+    seeder = Gitlab::Seeder::CycleAnalytics.new(Project.order(:id).first, perf: true)
+    seeder.seed_metrics!
   else
     puts "Not running the cycle analytics seed file. Use the `SEED_CYCLE_ANALYTICS` environment variable to enable it."
   end