Expand the README to explain what bootrr is about

Inspired by https://github.com/RichardLitt/standard-readme/

Signed-off-by: Emanuele Aina <emanuele.aina@collabora.com>

README

@@ -1,9 +0,0 @@
-
-- Steps to run bootrr locally (helpful while testing on local board or
-  creating new tests)
-
-	Clone the bootrr repo or use a tarball from repo
-	Run the below cmds for running tests for a given board locally
-
-	# export PATH=$PWD/helpers:$PATH
-	# ./boards/<file>

README.md

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+
+# Bootrr
+
+A sanity checker for boards under automated test on LAVA.
+
+Before running the tests for your software stack on LAVA, you really want to
+ensure that the basics are in place.
+
+Testing that all the expected hardware is detected and that modules and
+firmwares can be loaded catches some very common kind of regressions: for
+instance, when renaming identifiers it is often the case that firmware blobs no
+longer get loaded since their location needs to be updated accordingly.
+
+This repository contains:
+* static board descriptions that list what to expect for each specific
+  board type
+* helpers to inspect the current system and compare it against the static board
+  description for it
+* the `bootrr` script to automatically detect the current board and run
+  the matching tests
+
+The output is in a format meant to be directly parsed by LAVA.
+
+## Install
+
+```sh
+$ make prefix=/usr/local DESTDIR=/ install
+```
+
+## Usage
+
+```sh
+$ bootrr
+<LAVA_SIGNAL_TESTCASE TEST_CASE_ID=deferred-probe-empty RESULT=skip>
+<LAVA_SIGNAL_TESTCASE TEST_CASE_ID=all-cpus-are-online RESULT=pass>
+```
+
+## Related Efforts
+
+- [LAVA](https://lavasoftware.org/) - A continuous integration system for deploying operating systems onto physical and virtual hardware for running tests.
+- [KernelCI](https://kernelci.org/) - Community-led test system focused on the upstream Linux kernel.
+
+## License
+
+BSD-3-Clause