Add links to documentation to the rules_java README

Fixes https://github.com/bazelbuild/rules_java/issues/80

PiperOrigin-RevId: 698344251
Change-Id: Ibb5361c9aa7013f9a1eca36e0d4cee09c5c62bd3

README.md

diff --git a/README.md b/README.md
index 8c946de..e4cfeb0 100644
--- a/README.md
+++ b/README.md
@@ -4,3 +4,22 @@
 * Postsubmit + Current Bazel Incompatible Flags [![Build status](https://badge.buildkite.com/ef265d270238c02aff65106a0b861abb9265efacdf4af399c3.svg?branch=master)](https://buildkite.com/bazel/rules-java-plus-bazelisk-migrate)
 
 Java Rules for Bazel https://bazel.build.
+
+**Documentation**
+
+For a quickstart tutorial, see https://bazel.build/start/java
+
+For slightly more advanced usage, like setting up toolchains
+or writing your own java-like rules,
+see https://bazel.build/docs/bazel-and-java
+
+
+***Core Java rules***
+
+Add a load like:
+```build
+load("@rules_java//java:java_library.bzl", "java_library")
+```
+to your `BUILD` / `BUILD.bazel` / bzl` files
+
+For detailed docs on the core rules, see https://bazel.build/reference/be/java