Fix not actually connecting to the configured replica (#25977)

app/helpers/database_helper.rb

@@ -2,10 +2,10 @@
 
 module DatabaseHelper
   def with_read_replica(&block)
-    ApplicationRecord.connected_to(role: :read, prevent_writes: true, &block)
+    ApplicationRecord.connected_to(role: :reading, prevent_writes: true, &block)
   end
 
   def with_primary(&block)
-    ApplicationRecord.connected_to(role: :primary, &block)
+    ApplicationRecord.connected_to(role: :writing, &block)
   end
 end

app/models/application_record.rb

@@ -5,6 +5,8 @@ class ApplicationRecord < ActiveRecord::Base
 
   include Remotable
 
+  connects_to database: { writing: :primary, reading: :read }
+
   class << self
     def update_index(_type_name, *_args, &_block)
       super if Chewy.enabled?

config/database.yml

@@ -8,23 +8,41 @@ default: &default
   application_name: ''
 
 development:
+  primary:
     <<: *default
     database: <%= ENV['DB_NAME'] || 'mastodon_development' %>
     username: <%= ENV['DB_USER'] %>
     password: <%= (ENV['DB_PASS'] || '').to_json %>
     host: <%= ENV['DB_HOST'] %>
     port: <%= ENV['DB_PORT'] %>
+  read:
+    <<: *default
+    database: <%= ENV['DB_NAME'] || 'mastodon_development' %>
+    username: <%= ENV['DB_USER'] %>
+    password: <%= (ENV['DB_PASS'] || '').to_json %>
+    host: <%= ENV['DB_HOST'] %>
+    port: <%= ENV['DB_PORT'] %>
+    replica: true
 
 # Warning: The database defined as "test" will be erased and
 # re-generated from your development database when you run "rake".
 # Do not set this db to the same as development or production.
 test:
+  primary:
     <<: *default
     database: <%= ENV['DB_NAME'] || 'mastodon' %>_test<%= ENV['TEST_ENV_NUMBER'] %>
     username: <%= ENV['DB_USER'] %>
     password: <%= (ENV['DB_PASS'] || '').to_json %>
     host: <%= ENV['DB_HOST'] %>
     port: <%= ENV['DB_PORT'] %>
+  read:
+    <<: *default
+    database: <%= ENV['DB_NAME'] || 'mastodon' %>_test<%= ENV['TEST_ENV_NUMBER'] %>
+    username: <%= ENV['DB_USER'] %>
+    password: <%= (ENV['DB_PASS'] || '').to_json %>
+    host: <%= ENV['DB_HOST'] %>
+    port: <%= ENV['DB_PORT'] %>
+    replica: true
 
 production:
   primary: