In general @> is the “contains” operator.
It is defined for several data types.
- arrays: http://www.postgresql.org/docs/current/static/functions-array.html
- range types: http://www.postgresql.org/docs/current/static/functions-range.html
- geometric types: http://www.postgresql.org/docs/current/static/functions-geometry.html
- JSON (and JSONB): http://www.postgresql.org/docs/current/static/functions-json.html