Extract method to get a few random records

In Ruby 5.2, we get a warning when using the "RANDOM()" function:

DEPRECATION WARNING: Dangerous query method (method whose arguments are
used as raw SQL) called with non-attribute argument(s): "RANDOM()".
Non-attribute arguments will be disallowed in Rails 6.0. This method
should not be called with user-provided values, such as request
parameters or model attributes. Known-safe values can be passed by
wrapping them in Arel.sql().

This warning doesn't make much sense, though, since RANDOM() is a common
function which is not dangerous at all. However, since the warning is
annoying, we'll probably have to find a way to deal with it.

So I'm extracting all our RANDOM() usages into a method. This way we'll
only have to change one method to avoid this warning.

I've chosen `sample` because it's similar to Ruby's Array#sample, and
because `order_by_random` would be confusing if we consider we already
have a method called `sort_by_random`.

app/models/application_record.rb

@@ -1,3 +1,11 @@
 class ApplicationRecord < ActiveRecord::Base
   self.abstract_class = true
+
+  def self.sample(count = 1)
+    if count == 1
+      reorder("RANDOM()").first
+    else
+      reorder("RANDOM()").limit(count)
+    end
+  end
 end

db/dev_seeds/budgets.rb

@@ -147,7 +147,7 @@ end
 
 section "Marking investments as visible to valuators" do
   (1..50).to_a.sample.times do
-    Budget::Investment.reorder("RANDOM()").first.update(visible_to_valuators: true)
+    Budget::Investment.sample.update(visible_to_valuators: true)
   end
 end
 

db/dev_seeds/flags.rb

@@ -19,7 +19,7 @@ section "Flagging Debates & Comments" do
 end
 
 section "Ignoring flags in Debates, comments & proposals" do
-  Debate.flagged.reorder("RANDOM()").limit(10).each(&:ignore_flag)
-  Comment.flagged.reorder("RANDOM()").limit(30).each(&:ignore_flag)
-  Proposal.flagged.reorder("RANDOM()").limit(10).each(&:ignore_flag)
+  Debate.flagged.sample(10).each(&:ignore_flag)
+  Comment.flagged.sample(30).each(&:ignore_flag)
+  Proposal.flagged.sample(10).each(&:ignore_flag)
 end

db/dev_seeds/hiddings.rb

@@ -1,11 +1,11 @@
 section "Hiding debates, comments & proposals" do
-  Comment.with_hidden.flagged.reorder("RANDOM()").limit(30).each(&:hide)
-  Debate.with_hidden.flagged.reorder("RANDOM()").limit(5).each(&:hide)
-  Proposal.with_hidden.flagged.reorder("RANDOM()").limit(10).each(&:hide)
+  Comment.with_hidden.flagged.sample(30).each(&:hide)
+  Debate.with_hidden.flagged.sample(5).each(&:hide)
+  Proposal.with_hidden.flagged.sample(10).each(&:hide)
 end
 
 section "Confirming hiding in debates, comments & proposals" do
-  Comment.only_hidden.flagged.reorder("RANDOM()").limit(10).each(&:confirm_hide)
-  Debate.only_hidden.flagged.reorder("RANDOM()").limit(5).each(&:confirm_hide)
-  Proposal.only_hidden.flagged.reorder("RANDOM()").limit(5).each(&:confirm_hide)
+  Comment.only_hidden.flagged.sample(10).each(&:confirm_hide)
+  Debate.only_hidden.flagged.sample(5).each(&:confirm_hide)
+  Proposal.only_hidden.flagged.sample(5).each(&:confirm_hide)
 end

db/dev_seeds/notifications.rb

@@ -4,10 +4,10 @@ section "Creating comment notifications" do
                             title: Faker::Lorem.sentence(3).truncate(60),
                             description: "<p>#{Faker::Lorem.paragraphs.join("</p><p>")}</p>",
                             tag_list: Tag.all.sample(3).join(","),
-                            geozone: Geozone.reorder("RANDOM()").first,
+                            geozone: Geozone.sample,
                             terms_of_service: "1")
 
-    comment = Comment.create!(user: User.reorder("RANDOM()").first,
+    comment = Comment.create!(user: User.sample,
                               body: Faker::Lorem.sentence,
                               commentable: debate)
 

db/dev_seeds/polls.rb

@@ -13,7 +13,7 @@ section "Creating polls" do
                starts_at: 5.days.ago,
                ends_at:   5.days.from_now,
                geozone_restricted: true,
-               geozones: Geozone.reorder("RANDOM()").limit(3))
+               geozones: Geozone.sample(3))
 
   Poll.create!(name: I18n.t("seeds.polls.recounting_poll"),
                slug: I18n.t("seeds.polls.recounting_poll").parameterize,