List sources not in a channel on channel edit page

core/channel.go

@@ -22,6 +22,11 @@ func GetSourcesInChannel(db DB) (map[string][]string, error) {
 	rows, err := db.Query(`
 		select name, source
 		from channels
+		union
+		select '' as name, sources.name as source
+		from sources
+		left outer join channels on channels.source = sources.name
+		where channels.name is null
 		order by name, source
 	`)
 	if err != nil {

web/html/editChannels.html

@@ -29,6 +29,7 @@
 </datalist>
 
 {{ range $channel, $sources := .ChannelSources }}
+{{ if $channel }}
 <p><b><a href="/channel/{{ $channel }}">{{ $channel }}</a></b></p>
 <table>
 {{- range $sources }}
@@ -42,8 +43,17 @@
 <td><a href="/source/{{ . }}">{{ . }}</a></td>
 </tr>
 {{ end }}
-
 </table>
 {{ end }}
+{{ end }}
+
+{{ if index .ChannelSources "" }}
+<p><b>not in a channel</b></p>
+<ul>
+{{ range index .ChannelSources "" }}
+<li><a href="/source/{{ . }}">{{ . }}</a></li>
+{{ end }}
+</ul>
+{{ end }}
 </nav>
 {{- end }}