add basic create and list reminder api

Budet-cho-bot/Repositories/CronRepository.cs

@@ -0,0 +1,33 @@
+using Budet_cho_bot.Helpers;
+using Discord_Bot;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Budet_cho_bot.Repositories
+{
+    public class CronRepository
+    {
+        public async Task<int> SetCronTask(string taskType, string task)
+        {
+            var config = Functions.GetConfig();
+            config[taskType] = task;
+            Functions.SaveConfig(config);
+
+            return 1;
+        }
+
+        public async Task<string> GetCronTask(string taskType)
+        {
+            var config = Functions.GetConfig();
+            if (config.TryGetValue(taskType, out var tasks))
+            {
+                return tasks.ToString();
+            }
+
+            return null;
+        }
+    }
+}