Add a function to get the SECRET enviroment variable.

src/main/blog/env.cljs

@@ -7,6 +7,15 @@
           (.-PORT))
       "3000"))
 
+(defn get-secret
+  "Gets the environment variable SECRET. If no variable, then the server will be crashed."
+  []
+  (or (-> (.-env js/process)
+          (.-SECRET))
+      (do
+        (js/console.log "[ERROR] Set enviroment variable SECRET!!!")
+        (js/process.exit 1))))
+
 (defn get-database-credentials
   "Gets the postgres credentials. Defaults: host - postgres, port - 5432, database - postgres, user - postgres, password - 'changeme!!!'."
   []