Add a task to mask existing IPs collected with Ahoy

According to the README [1]:

> To mask previously collected IPs, use:
> Ahoy::Visit.find_each do |visit|
>   visit.update_column :ip, Ahoy.mask_ip(visit.ip)
> end

We're adapting the code with our version, since we use the `Visit` model
instead of the `Ahoy::Visit` model.

[1] https://github.com/ankane/ahoy/blob/v5.0.2/README.md#ip-masking

lib/tasks/consul.rake

@@ -2,8 +2,10 @@ namespace :consul do
   desc "Runs tasks needed to upgrade to the latest version"
   task execute_release_tasks: ["settings:rename_setting_keys",
                                "settings:add_new_settings",
-                               "execute_release_2.1.0_tasks"]
+                               "execute_release_2.2.0_tasks"]
 
-  desc "Runs tasks needed to upgrade from 2.0.1 to 2.1.0"
+  desc "Runs tasks needed to upgrade from 2.1.1 to 2.2.0"
-  task "execute_release_2.1.0_tasks": []
+  task "execute_release_2.2.0_tasks": [
+    "db:mask_ips"
+  ]
 end

lib/tasks/db.rake

@@ -4,4 +4,15 @@ namespace :db do
     I18n.enforce_available_locales = false
     Tenant.switch(args[:tenant]) { load(Rails.root.join("db", "dev_seeds.rb")) }
   end
+
+  desc "Mask IPs collected with Ahoy"
+  task mask_ips: :environment do
+    ApplicationLogger.new.info "Masking tracked IPs collected with Ahoy"
+
+    Tenant.run_on_each do
+      Visit.find_each do |visit|
+        visit.update_column :ip, Ahoy.mask_ip(visit.ip)
+      end
+    end
+  end
 end

spec/lib/tasks/db_spec.rb

@@ -0,0 +1,27 @@
+require "rails_helper"
+
+describe "rake db:mask_ips" do
+  before { Rake::Task["db:mask_ips"].reenable }
+
+  it "mask IPs on all tenants" do
+    create(:visit, ip: "1.1.1.1")
+    create(:visit, ip: "1.1.1.2")
+    create(:visit, ip: "1.1.2.2")
+
+    create(:tenant, schema: "myhometown")
+
+    Tenant.switch("myhometown") do
+      create(:visit, ip: "1.1.1.1")
+      create(:visit, ip: "1.1.1.2")
+      create(:visit, ip: "1.1.3.3")
+    end
+
+    Rake.application.invoke_task("db:mask_ips")
+
+    expect(Visit.pluck(:ip)).to match_array %w[1.1.1.0 1.1.1.0 1.1.2.0]
+
+    Tenant.switch("myhometown") do
+      expect(Visit.pluck(:ip)).to match_array %w[1.1.1.0 1.1.1.0 1.1.3.0]
+    end
+  end
+end