Use 127.0.0.1 instead of localhost so Docker DB can be easily used (rails#52778)

* Use 127.0.0.1 instead of localhost so Docker DB can be easily used

* Fix tests

Author: dhh

railties/lib/rails/generators/database.rb

@@ -42,7 +42,7 @@ def socket
         end
 
         def host
-          "localhost"
+          "127.0.0.1"
         end
       end
 

railties/test/generators/app_generator_test.rb

@@ -1365,7 +1365,7 @@ def test_devcontainer_mysql
       assert_includes content["forwardPorts"], 3306
     end
     assert_file("config/database.yml") do |content|
-      assert_match(/host: <%= ENV.fetch\("DB_HOST"\) \{ "localhost" } %>/, content)
+      assert_match(/host: <%= ENV.fetch\("DB_HOST"\) \{ "127.0.0.1" } %>/, content)
     end
   end
 
@@ -1393,7 +1393,7 @@ def test_devcontainer_trilogy
       assert_includes(content["forwardPorts"], 3306)
     end
     assert_file("config/database.yml") do |content|
-      assert_match(/host: <%= ENV.fetch\("DB_HOST"\) \{ "localhost" } %>/, content)
+      assert_match(/host: <%= ENV.fetch\("DB_HOST"\) \{ "127.0.0.1" } %>/, content)
     end
   end
 
@@ -1421,7 +1421,7 @@ def test_devcontainer_mariadb_mysql
       assert_includes(content["forwardPorts"], 3306)
     end
     assert_file("config/database.yml") do |content|
-      assert_match(/host: <%= ENV.fetch\("DB_HOST"\) \{ "localhost" } %>/, content)
+      assert_match(/host: <%= ENV.fetch\("DB_HOST"\) \{ "127.0.0.1" } %>/, content)
     end
   end
 
@@ -1448,7 +1448,7 @@ def test_devcontainer_mariadb_trilogy
       assert_includes(content["forwardPorts"], 3306)
     end
     assert_file("config/database.yml") do |content|
-      assert_match(/host: <%= ENV.fetch\("DB_HOST"\) \{ "localhost" } %>/, content)
+      assert_match(/host: <%= ENV.fetch\("DB_HOST"\) \{ "127.0.0.1" } %>/, content)
     end
   end