Add example to try and reproduce failure.

Author: ioquatix

examples/pgfault/config.ru

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+# frozen_string_literal: true
+
+require "pg"
+
+run do |env|
+	connection = PG.connect(dbname: "test")
+	result = connection.exec("SELECT 1")
+	Console.info(self, "Connection established to PostgreSQL database", result: result.to_a, connection: connection)
+	connection.close
+	
+	[200, {"content-type" => "text/plain"}, ["Hello, World!"]]
+end

examples/pgfault/falcon.rb

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+# frozen_string_literal: true
+
+require "pg"
+require "falcon/environment/rack"
+
+connection = PG.connect(dbname: "test")
+result = connection.exec("SELECT 1")
+Console.info(self, "Connection established to PostgreSQL database", result: result.to_a, connection: connection)
+connection.close
+
+service "hello.localhost" do
+	include Falcon::Environment::Rack
+	
+	endpoint do
+		Async::HTTP::Endpoint.parse("http://hello.localhost:9292")
+	end
+	
+	preload "preload.rb"
+end

examples/pgfault/gems.rb

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+# frozen_string_literal: true
+
+source "https://rubygems.org"
+
+gem "pg"
+gem "falcon"

examples/pgfault/preload.rb

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+
+require "pg"
+
+connection = PG.connect(dbname: "test")
+result = connection.exec("SELECT 1")
+Console.info(self, "Connection established to PostgreSQL database", result: result.to_a, connection: connection)
+connection.close

examples/pgfault/readme.md

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+# PG Segfault
+
+On macOS, some usage of the Objective-C runtime can cause issues when forking. This can lead to a segmentation fault when using the `pg` gem with Falcon, but I've not been able to reproduce it thus far. If you encounter this, please report it: <https://github.com/socketry/falcon/issues/225>.
+
+## Usage
+
+### Postgres Setup
+
+- Create a data directory.
+- `initdb -D data/`
+- `pg_ctl -D data/ start`
+- `createdb test`
+
+(To stop, run `pg_ctl -D data/ stop`.)
+
+### Run the server
+
+```bash
+bundle exec falcon host
+```
+
+Then visit <http://hello.localhost:9292>, e.g.
+
+```bash
+curl http://hello.localhost:9292
+```
+
+You should see "Hello, World!" in the response (and no errors/segfaults in the server logs).