[Documentation Issue] deprecated method

Page Name: bigquery-usage
Release: 0.8.0

In the documentation of bigquery usage -> insert data (sync)

``` python
job = table.load_from_file(
    file_obj, source_format='CSV', skip_leading_rows=1,
    write_disposition='truncate')
```

According to your table doc, the method `load_from_file` is not supported anymore.
