Avoid redundant OAuth queries when not signed in

If you aren't signed in, you don't have an auth token.
When you don't have an auth token, React was sending the headers

"Authorization: Bearer null"

This caused 5 Doorkeeper token lookups using
WHERE "oauth_access_tokens"."token" = 'null'
on the Explore page (the root of the app when not signed in).

config/database.yml

@@ -7,7 +7,7 @@ default: &default
   prepared_statements: <%= ENV['PREPARED_STATEMENTS'] || 'false' %>
 
 development:
-  master:
+  primary:
     <<: *default
     url: <%= ENV['DB_MASTER_URL'] %>
   slave1:
@@ -39,7 +39,7 @@ test:
 #  port: <%= ENV['DB_PORT'] || 5432 %>
 #  prepared_statements: <%= ENV['PREPARED_STATEMENTS'] || 'true' %>
 production:
-  master:
+  primary:
     <<: *default
     url: <%= ENV['DB_MASTER_URL'] %>
   slave1:

config/initializers/devise.rb

@@ -76,6 +76,14 @@ module Devise
 end
 
 Devise.setup do |config|
+
+  config.warden_hook_save_wrapper = Proc.new do |hook|
+    # ensure the writable connection is used to avoid read-only write errors
+    ApplicationRecord.connected_to(role: :writing) do
+      hook.call
+    end
+  end
+
   config.warden do |manager|
     manager.default_strategies(scope: :user).unshift :ldap_authenticatable if Devise.ldap_authentication
     manager.default_strategies(scope: :user).unshift :pam_authenticatable  if Devise.pam_authentication

config/initializers/omniauth.rb

@@ -7,6 +7,13 @@ Devise.setup do |config|
   options = {}
   options[:redirect_at_sign_in] = ENV['OAUTH_REDIRECT_AT_SIGN_IN'] == 'true'
 
+  config.warden_hook_save_wrapper = Proc.new do |hook|
+    # ensure the writable connection is used to avoid read-only write errors
+    ApplicationRecord.connected_to(role: :writing) do
+      hook.call
+    end
+  end
+  
   # CAS strategy
   if ENV['CAS_ENABLED'] == 'true'
     cas_options = options