[Feature Request] Database Migrations

**Feature Request**
Feature Request

**Describe the feature request or bug**
After an update from version 0.5 to version 0.6, when we start covenant, it fails with an sqlite error.

If I understand correctly, you do not update the database. We need to remove the covenant.db to "fix" this.

**To Reproduce**
1. Install version 0.5 (by installing dotnet core)
2. Run covenant at least once to create the database
3. Update covenant to version 0.6
4. Run covenant
5. `An exception occurred while iterating over the results of a query for context type 'Covenant.Models.CovenantContext'.
Microsoft.Data.Sqlite.SqliteException (0x80004005): SQLite Error 1: 'no such table: Themes'.`

**Expected behavior**
There should be no need to delete the database. I think you should handle the db upgrade.

**Target Information (System that implant is running on):**
- OS: kali