add yaml_db gem

Gemfile

@@ -54,6 +54,8 @@ end
 group :development do
   # Use console on exceptions pages [https://github.com/rails/web-console]
   gem "web-console"
+
+  gem "yaml_db"
 end
 
 group :test do

Gemfile.lock

@@ -346,6 +346,9 @@ GEM
     websocket-extensions (0.1.5)
     xpath (3.2.0)
       nokogiri (~> 1.8)
+    yaml_db (0.7.0)
+      rails (>= 3.0)
+      rake (>= 0.8.7)
     zeitwerk (2.7.3)
 
 PLATFORMS
@@ -380,6 +383,7 @@ DEPENDENCIES
   turbo-rails
   tzinfo-data
   web-console
+  yaml_db
 
 BUNDLED WITH
    2.6.6