Added migrations

EventArguments/MigrationCompletedEventArgs.cs

@@ -0,0 +1,20 @@
+using System;
+
+namespace DbTools.EventArguments {
+    public delegate void MigrationCompletedEventHandler(object sender, MigrationCompletedEventArgs e);
+
+    public class MigrationCompletedEventArgs : EventArgs {
+        public string MigrationName { get; set; }
+        public bool WasSuccessful { get; set; }
+        public Exception Error { get; set; }
+        public int Remaining { get; set; }
+
+        public MigrationCompletedEventArgs() { }
+        public MigrationCompletedEventArgs(string migrationName, int remaining, Exception error = null, bool wasSuccessful = true) {
+            MigrationName = migrationName;
+            WasSuccessful = error != null ? false : wasSuccessful;
+            Error = error;
+            Remaining = remaining;
+        }
+    }
+}