Separate `target to additional host` field

So that we could actually generate proper urls

res/ExampleConfig-documented.edn

@@ -15,9 +15,13 @@
                    ;; Default ChOD to use if none is specified by the user
                    :default-chod 94
                    ;; If you want to do some preprocessing beforehand, you can override
-                   ;; Target URL for the board, but the response must be same the 4chan API would return
+                   ;; target URL for the board, but the response must be same the 4chan API would return
                    ;; /$board/catalog.json will be appended to this link
+                   ;; This is target for API requests
                    :target "https://api.4chan.org"
+                   ;; This host that has the actual threads, /board/thread-no will be appeneded
+                   ;; to this
+                   :host "https://boards.4chan.org"
                    ;; Commented parts bellow are still unimplemented
                    ;; ------
                    ;; Only download catalog when someone requests feed and cache is old

src/rss_thread_watch/feed_generator.clj

@@ -103,7 +103,7 @@
               :description "RSS based thread watcher"}
         body (map #(thread-to-rss-item
                     %1
-                    (get board-config :target)
+                    (get board-config :host)
                     (get board-config :name)) items)]
     (rss/channel-xml head body)))