Updated and added various models

This commit includes functionality for many of the models that the
program will use. The transaction model, rate, and room model have been
implemented, but still need further review to determine if they are
finished. The same applies to guest and reservation. Currently all
models include a simple list class, the decision to use a database or
a serialized object (JSON, array, list, etc). These lists are currently
a placeholder and are not guaranteed to land in main.

OpheliasOasis/Models/Rate.cs

@@ -0,0 +1,33 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Ophelias.Models;
+
+namespace Ophelias.Models
+{
+    internal class BaseRate
+    {
+        internal int Id;
+        internal double Rate;
+        internal DateTime DateSet;
+
+        internal BaseRate(int id, double rate)
+        {
+            Id = id;
+            Rate = rate;
+            DateSet = DateTime.Now;
+        }  
+    }
+
+    internal class Rates
+    {
+        internal List<BaseRate> BaseRates;
+
+        internal Rates()
+        {
+            BaseRates = new List<BaseRate>();
+        }
+    }
+}