Add a bit to the README about building the benchmark

benchmarks/lobsters/README.md

@@ -1,3 +1,11 @@
+# Lobsters Benchmark
+
+The YJIT team started from the Lobsters source code on GitHub. We created a fairly simple route generator, including randomising data items, login and CSRF tokens.
+
+The hope is that this will act as a step in between extremely simple Rails-based benchmarks (railsbench, erubi_rails) and significantly more complex Rails apps like Discourse with more non-Ruby dependencies, more I/O and database time, and more obstacles to easy benchmarking.
+
+## Original Lobste.rs README follows
+
 ### Lobsters Rails Project ![build status](https://github.com/lobsters/lobsters/actions/workflows/check.yml/badge.svg)
 
 This is the