- Add storing bot response messages in postgres

- Add scheduled task to clean up said store

PluralKit.Bot/Bot.cs

@@ -9,6 +9,8 @@ using App.Metrics;
 
 using Autofac;
 
+using Dapper;
+
 using DSharpPlus;
 using DSharpPlus.Entities;
 using DSharpPlus.EventArgs;
@@ -34,18 +36,21 @@ namespace PluralKit.Bot
         private readonly PeriodicStatCollector _collector;
         private readonly IMetrics _metrics;
         private readonly ErrorMessageService _errorMessageService;
+        private readonly IDatabase _db;
 
         private bool _hasReceivedReady = false;
         private Timer _periodicTask; // Never read, just kept here for GC reasons
 
-        public Bot(DiscordShardedClient client, ILifetimeScope services, ILogger logger, PeriodicStatCollector collector, IMetrics metrics, ErrorMessageService errorMessageService)
+        public Bot(DiscordShardedClient client, ILifetimeScope services, ILogger logger, PeriodicStatCollector collector, IMetrics metrics, 
+            ErrorMessageService errorMessageService, IDatabase db)
         {
             _client = client;
+            _logger = logger.ForContext<Bot>();
             _services = services;
             _collector = collector;
             _metrics = metrics;
             _errorMessageService = errorMessageService;
-            _logger = logger.ForContext<Bot>();
+            _db = db;
         }
 
         public void Init()
@@ -177,6 +182,9 @@ namespace PluralKit.Bot
 
             await UpdateBotStatus();
 
+            // Clean up message cache in postgres
+            await _db.Execute(conn => conn.QueryAsync("select from cleanup_command_message()"));
+
             // Collect some stats, submit them to the metrics backend
             await _collector.CollectStats();
             await Task.WhenAll(((IMetricsRoot) _metrics).ReportRunner.RunAllAsync());