Unit tests show which command is being run

- helps me troubleshoot; I get lost at times.
- README shows more verbose variant of rspec

README.md

@@ -14,7 +14,7 @@ Refer to the website ([sslip.io](https://sslip.io)) for more information.
 - `spec/` contains the RSpec files for test driven development (TDD).
   To run the tests:
 ```bash
-DOMAIN=sslip.io rspec spec/
+DOMAIN=sslip.io rspec --format documentation --color spec
 ```
 - `conf/sslip.io+nono.io.yml` contains the
   [PowerDNS](https://www.powerdns.com/)'s [pipe

spec/check-dns_spec.rb

@@ -38,7 +38,8 @@ describe domain do
   end
 
   whois_nameservers.each do |whois_nameserver|
-    it "nameserver #{whois_nameserver}'s NS records match whois's #{whois_nameservers}" do
+    it "nameserver #{whois_nameserver}'s NS records match whois's #{whois_nameservers}, " +
+      "`dig +short ns sslip.io @#{whois_nameserver}`" do
       dig_nameservers = `dig +short ns sslip.io @#{whois_nameserver}`.split(/\n+/)
       expect(dig_nameservers.sort).to eq(whois_nameservers.sort)
     end