Make master key added to gitignore the same value as when creating appplication

For gitignore generated by `rails new`, key with a leading slash is specified.
https://github.com/rails/rails/blob/69f976b859cae7f9d050152103da018b7f5dda6d/railties/lib/rails/generators/rails/app/templates/gitignore#L11

Therefore, when executing `credentials:edit`, also need leading slack.
In order to avoid such a difference, fixed to use same method for
`rails new` and `credentials:edit`.

2 files changed, 15 insertions, 16 deletions

diff --git a/railties/lib/rails/generators/rails/app/templates/gitignore b/railties/lib/rails/generators/rails/app/templates/gitignore
index c37f01a848..83a7b211aa 100644
--- a/railties/lib/rails/generators/rails/app/templates/gitignore
+++ b/railties/lib/rails/generators/rails/app/templates/gitignore
@@ -7,9 +7,6 @@
 # Ignore bundler config.
 /.bundle
 
-# Ignore master key for decrypting credentials and more.
-/config/master.key
-
 <% if sqlite3? -%>
 # Ignore the default SQLite database.
 /db/*.sqlite3
diff --git a/railties/lib/rails/generators/rails/master_key/master_key_generator.rb b/railties/lib/rails/generators/rails/master_key/master_key_generator.rb
index 36a0b69e76..a79e83495a 100644
--- a/railties/lib/rails/generators/rails/master_key/master_key_generator.rb
+++ b/railties/lib/rails/generators/rails/master_key/master_key_generator.rb
@@ -22,6 +22,8 @@ module Rails
           say ""
           add_master_key_file_silently key
           say ""
+
+          ignore_master_key_file
         end
       end
 
@@ -29,24 +31,24 @@ module Rails
         create_file MASTER_KEY_PATH, key || ActiveSupport::EncryptedFile.generate_key
       end
 
-      def ignore_master_key_file
-        if File.exist?(".gitignore")
-          unless File.read(".gitignore").include?(key_ignore)
-            say "Ignoring #{MASTER_KEY_PATH} so it won't end up in Git history:"
-            say ""
-            append_to_file ".gitignore", key_ignore
+      private
+        def ignore_master_key_file
+          if File.exist?(".gitignore")
+            unless File.read(".gitignore").include?(key_ignore)
+              say "Ignoring #{MASTER_KEY_PATH} so it won't end up in Git history:"
+              say ""
+              append_to_file ".gitignore", key_ignore
+              say ""
+            end
+          else
+            say "IMPORTANT: Don't commit #{MASTER_KEY_PATH}. Add this to your ignore file:"
+            say key_ignore, :on_green
             say ""
           end
-        else
-          say "IMPORTANT: Don't commit #{MASTER_KEY_PATH}. Add this to your ignore file:"
-          say key_ignore, :on_green
-          say ""
         end
-      end
 
-      private
         def key_ignore
-          [ "", "# Ignore master key for decrypting credentials and more.", MASTER_KEY_PATH, "" ].join("\n")
+          [ "", "# Ignore master key for decrypting credentials and more.", "/#{MASTER_KEY_PATH}", "" ].join("\n")
         end
     end
   end