use dapper in a few places (#29)

* use dapper in a few places

* use single dapper queries

ErsatzTV.Infrastructure/Data/SqliteTypeHandlers.cs

@@ -0,0 +1,32 @@
+using System;
+using System.Data;
+using Dapper;
+
+namespace ErsatzTV.Infrastructure.Data
+{
+    public abstract class SqliteTypeHandler<T> : SqlMapper.TypeHandler<T>
+    {
+        // Parameters are converted by Microsoft.Data.Sqlite
+        public override void SetValue(IDbDataParameter parameter, T value)
+            => parameter.Value = value;
+    }
+
+    public class DateTimeOffsetHandler : SqliteTypeHandler<DateTimeOffset>
+    {
+        public override DateTimeOffset Parse(object value)
+            => DateTimeOffset.Parse((string)value);
+    }
+
+    public class GuidHandler : SqliteTypeHandler<Guid>
+    {
+        public override Guid Parse(object value)
+            => Guid.Parse((string)value);
+    }
+
+    public class TimeSpanHandler : SqliteTypeHandler<TimeSpan>
+    {
+        public override TimeSpan Parse(object value)
+            => TimeSpan.Parse((string)value);
+    }
+
+}