README is more developer-friendly with Quick Start

This repo has been forked 36 times, and yet I've done a great disservice
to my would-be developers by not describing how to run/test my code.

This commit addresses that shortcoming by having a _Quick Start_ section
very near the top.

- includes new Ginkgo v2
- includes required `sudo` for Linux
- removed the now-wrong comment about TXT records (there's now a
  plethora of TXT records such as `ip.sslip.io`)
- minor formatting tweaks

README.md

@@ -5,14 +5,40 @@
 | Production Nameservers | [![ci.nono.io](https://ci.nono.io/api/v1/pipelines/sslip.io/jobs/dns-servers/badge)](https://ci.nono.io/teams/main/pipelines/sslip.io) |
 | DNS Server Unit Tests | [![ci.nono.io](https://ci.nono.io/api/v1/pipelines/sslip.io/jobs/unit/badge)](https://ci.nono.io/teams/main/pipelines/sslip.io) |
 
-*sslip.io* is a DNS server that maps specially-crafted DNS A records to IP addresses
+*sslip.io* is a DNS server that maps specially-crafted DNS A records to IP
-(e.g. "127-0-0-1.sslip.io" maps to 127.0.0.1). It is similar to, and inspired by,
+addresses (e.g. "127-0-0-1.sslip.io" maps to 127.0.0.1). It is similar to, and
-[xip.io](http://xip.io/).
+inspired by, [xip.io](http://xip.io/).
 
 If you'd like to use sslip.io _as a service_, refer to the website
 ([sslip.io](https://sslip.io)) for more information. This README targets
 developers; the website targets users.
 
+## Quick Start
+
+```bash
+git clone git@github.com:cunnie/sslip.io.git
+cd sslip.io/bosh-release/src/sslip.io-dns-server/
+sudo go run main.go
+ # sudo is required on Linux, but not on macOS, to bind to privileged port 53
+```
+
+In another window:
+```bash
+dig @localhost 192.168.0.1.sslip.io +short
+ # should return "192.168.0.1"
+```
+
+## Quick Start Tests
+
+```bash
+go get github.com/onsi/ginkgo/v2/ginkgo
+go get github.com/onsi/gomega/...
+sudo ~/go/bin/ginkgo -r .
+ # sudo is required on Linux, but not on macOS, to bind to privileged port 53
+```
+
+## Directory Structure
+
 - `src/` contains the source code to the DNS server.
 - `ci/` contains the [Concourse](https://concourse.ci/) continuous integration
   (CI) pipeline and task.
@@ -35,48 +61,22 @@ the source:
 
 - it binds to port 53 (you can't change it)
 - it only binds to UDP (no TCP, sorry)
-- The SOA record is hard-coded with the exception of the _MNAME_ (primary master
+- The SOA record is hard-coded with the exception of the _MNAME_ (primary
-  name server) record, which is set to the queried hostname (e.g. `dig
+  master name server) record, which is set to the queried hostname (e.g. `dig
   big.apple.com @ns-aws.nono.io` would return an SOA with an _MNAME_ record of
   `big.apple.com.`
-- The NS records are hard-coded
+- The NS records are hard-coded (`ns-aws.sslip.io`, `ns-azure.sslip.io`,
+  `ns-gce.sslip.io`)
 - The MX records are hard-coded to the queried hostname with a preference of 0,
-  with the exception of `sslip.io` itself, which has custom MX records to enable
+  with the exception of `sslip.io` itself, which has custom MX records to
-  email delivery to ProtonMail.
+  enable email delivery to ProtonMail
-- No TXT records are returned with the exception of `sslip.io`, which has custom
-  records to enable email delivery
 - There are no SRV records
 
-To run the unit tests:
-```
-cd src
-go get github.com/onsi/ginkgo/ginkgo
-go get github.com/onsi/gomega/...
-ginkgo -r .
-```
-
-To run the server on, say, a Mac, you must first start the server:
-```
-cd src
-go run main.go
-```
-And then, in another window, run a query, e.g.:
-```
-dig +short 127.0.0.1.sslip.io @localhost
-```
-Which will return the expected IP address:
-```
-127.0.0.1
-```
-You will also see a log message in the server window, similar to the
-following:
-```
-2020/11/22 03:45:44 ::1.62302 TypeA 127.0.0.1.sslip.io. ? 127.0.0.1
-```
-
 ### Acknowledgements
 
-- Sam Stephenson (xip.io), Roopinder Singh (nip.io), and the other DNS developers out there
+- Sam Stephenson (xip.io), Roopinder Singh (nip.io), and the other DNS
+  developers out there
 - The contributors (@normanr, @jpambrun come to mind) who improved sslip.io
 - Jenessa Petersen of Let's Encrypt who bumped the rate limits
-- Natalia Ershova of JetBrains who provided a free license for [open source development](https://www.jetbrains.com/community/opensource/#support)
+- Natalia Ershova of JetBrains who provided a free license for [open source
+  development](https://www.jetbrains.com/community/opensource/#support)