update documentation to show how to use fluent mapping

[hahn-kev]

All the docs I found about fluent mapping look like this:

var myFluentMappings = new MappingSchema();
var builder       = mappingSchema.GetFluentMappingBuilder();

builder.Entity<Product>()
    .HasTableName("Products")
    .HasSchemaName("dbo")
    .HasIdentity(x => x.ProductID)
    .HasPrimaryKey(x => x.ProductID)
    .Ignore(x => x.SomeNonDbProperty)
    .Property(x => x.TimeStamp)
        .HasSkipOnInsert()
        .HasSkipOnUpdate()
    .Association(x => x.Vendor, x => x.VendorID, x => x.VendorID, canBeNull: false)
    ;

however there's no GetFluentMappingBuilder method defined anywhere in the whole code base, after looking around for a while I figured out that you're supposed to do this instead:

new FluentMappingBuilder(mappingSchema)
                    .HasAttribute<Commit>(new ColumnAttribute())
                    .Build();

docs should be updated to help people figure out what to do.

[AppChenX]

You can add the above code into the constructor