Support for getting token USD value

* utility function for getting current USD value of a crypto token
  from cryptonator API

src/clj/commiteth/util/crypto_fiat_value.clj

@@ -0,0 +1,14 @@
+(ns commiteth.util.crypto-fiat-value
+  (:require [clj-http.client :as http]
+            [clojure.data.json :as json]))
+
+
+(defn get-token-usd-price [token]
+  (let [url (str "https://api.cryptonator.com/api/ticker/"
+                 token
+                 "-usd")
+        m (->> (http/get url)
+               (:body)
+               (json/read-str))]
+    (-> (get-in m ["ticker" "price"])
+        (read-string))))