convertzone should do a better job with NS records. Fixes https://github.com/StackExchange/dnscontrol/issues/162

cmd/convertzone/README.md

@@ -1,5 +1,9 @@
 # convertzone -- Converts a standard DNS zonefile into tsv, pretty, or DSL
 
+This is a crude hack we put together to read a BIND-style zonefile
+and output a draft DNSControl dnsconfig.js file. It does about 90%
+of the work, but it isn't complete.
+
 ## Building the software
 
 Build the software and install in your personal bin:

cmd/convertzone/main.go

@@ -106,6 +106,11 @@ func rrFormat(zonename string, filename string, r io.Reader, defaultTTL uint32,
 			target = strings.Replace(target, " ", "\t", 1)
 		}
 
+		// NS records at the apex should be NAMESERVER() records.
+		if hdr.Rrtype == dns.TypeNS && name == "@" {
+			typeStr = "NAMESERVER"
+		}
+
 		if !dsl { // TSV format:
 			fmt.Printf("%s\t%s\t%s\t%s\t%s\n", name, ttl, classStr, typeStr, target)
 		} else { // DSL format: