Added first app template

backend/login-counter/app.Configuration/Constants.cs

@@ -0,0 +1,7 @@
+namespace app.Configuration {
+    public static class Constants {
+        public const string CustomerEnvironmentVariable = "CUSTOMER";
+        public const string ComputerNameEnvironmentVariable = "COMPUTERNAME";
+        public const string CustomersDirectoryName = "customers";
+    }
+}