added proper configuration using aero

src/book/core.clj

@@ -1,10 +1,15 @@
 (ns book.core
-  (:require [book.cli]
-            [book.web])
+  (:require [book.cli.core]
+            [book.rest.core]
+            [aero.core :refer (read-config)])
   (:gen-class))
 
+(def apps {:webserver book.rest.core/-main})
+
 (defn -main [& argv]
-  (case (first argv)
-    "web" (apply book.web/-main (rest argv))
-    "cli" (apply book.cli/-main (rest argv))
-    (println "First argument must be web or cli")))
+  (let [config (-> "config.edn" clojure.java.io/resource read-config)
+        target (-> argv first keyword)
+        target-fn (get apps target)]
+    (if target-fn
+      (apply target-fn [config])
+      (println "target" target "not found"))))