Merge branch 'seed-fu-award-emoji' into 'master'

Seed Award Emoji while seeding the database

## What does this MR do?

Lets `rake dev:setup` create award emoji on _some_ awardables. Seemed overkill to give all that privilege. 

See merge request !4555

db/fixtures/development/15_award_emoji.rb

+Gitlab::Seeder.quiet do
+  emoji = Gitlab::AwardEmoji.emojis.keys
+
+  Issue.order(Gitlab::Database.random).limit(Issue.count / 2).each do |issue|
+    project = issue.project
+
+    project.team.users.sample(2).each do |user|
+      issue.create_award_emoji(emoji.sample, user)
+
+      issue.notes.sample(2).each do |note|
+        next if note.system?
+        note.create_award_emoji(emoji.sample, user)
+      end
+
+      print '.'
+    end
+  end
+
+  MergeRequest.order(Gitlab::Database.random).limit(MergeRequest.count / 2).each do |mr|
+    project = mr.project
+
+    project.team.users.sample(2).each do |user|
+      mr.create_award_emoji(emoji.sample, user)
+
+      mr.notes.sample(2).each do |note|
+        next if note.system?
+        note.create_award_emoji(emoji.sample, user)
+      end
+
+      print '.'
+    end
+  end
+end

lib/gitlab/database.rb

@@ -30,6 +30,10 @@ module Gitlab
       order
     end
 
+    def self.random
+      Gitlab::Database.postgresql? ? "RANDOM()" : "RAND()"
+    end
+
     def true_value
       if Gitlab::Database.postgresql?
         "'t'"