Ruby Core Class Freezing Tool: Ruby Refrigerator

Ruby Refrigerator is a tool that freezes all Ruby core classes and modules, preventing unexpected modifications to core classes at runtime. It provides a `freeze_core` method to freeze core classes and a `check_require` method to check libraries for modifications to core classes. `check_require` supports options for predefining modules and classes, excluding specific classes, and specifying dependencies. A command-line tool, `bin/check_require`, is also provided for easy use. This tool is incredibly useful for ensuring code stability in production and testing environments.