IndexModel.add

IndexModel add(string field, int direction) ref return @safe

Adds a single field or multikey index with a direction.

Call this method multiple times with different fields to create a compound index.

`field`	the name of the field to index
`direction`	`1` for ascending or `-1` for descending

this IndexModel instance (caller)

IndexModel add(string field, string type) ref return @safe

Adds an index with a given index type. Use IndexType for a type-safe setting of the string.

`field`	the name of the field to index
`type`	the index type to use

this IndexModel instance (caller)