Improve Debugging with IRB section to make it easier to get started (#1015)

Author: st0012

README.md

@@ -170,6 +170,13 @@ Aliases
 
 ## Debugging with IRB
 
+### Getting Started
+
+- In `binding.irb`, use the `debug` command to start a `irb:rdbg` session with access to all `debug.gem` commands.
+- Use `RUBY_DEBUG_IRB_CONSOLE=1` environment variable to make `debug.gem` use IRB as the debugging console.
+
+### Details
+
 Starting from version 1.8.0, IRB boasts a powerful integration with `debug.gem`, providing a debugging experience akin to `pry-byebug`.
 
 After hitting a `binding.irb` breakpoint, you can activate the debugger with the `debug` command. Alternatively, if the `debug` method happens to already be defined in the current scope, you can call `irb_debug`.