finished documentation for installation, database usage and authentication

docs/installation/Database.md

@@ -0,0 +1,37 @@
+# Database initialization
+You also need to initialize the data source with the tables from HopFrame
+
+## Create a DbContext
+
+1. Create a c# class that inherits from the `HopDbContextBase` and add a data source (In the example Sqlite is used)
+
+    ```csharp
+    public class DatabaseContext : HopDbContextBase {
+       protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder) {
+           base.OnConfiguring(optionsBuilder);
+    
+           optionsBuilder.UseSqlite("...");
+       }
+    }
+    ```
+   
+    **IMPORTANT:** You need to leave the `base.OnConfiguring(optionsBuilder)` in place so the HopFrame model relations are set correctly.
+   <p>&nbsp;</p>
+
+2. Register the `DatabaseContext` as a service
+
+   ```csharp
+   builder.Services.AddDbContext<DatabaseContext>();
+   ```
+
+3. Create a database migration
+
+   ```bash
+   dotnet ef migrations add Initial
+   ```
+
+4. Apply the migration to the data source
+
+   ```bash
+   dotnet ef database update
+   ```