title: Bigquery add columns to table schema
body: <p>I am trying to add new column to BigQuery existing table. I have tried bq command tool and API approach. I get following error when making call to Tables.update(). </p>
  
  <p>I have tried with providing full schema with additional field and that also gives me same error as shown below.</p>
  
  <p>With API I get following Error:</p>
  
  <pre><code>{
      "schema": {
          "fields": [{
              "name": "added_column",
              "type": "integer",
              "mode": "nullable"
          }]
      }
  }
  
  
  
  {
      "error": {
          "errors": [{
              "domain": "global",
              "reason": "invalid",
              "message": "Provided Schema does not match Table [blah]"
          }],
          "code": 400,
          "message": "Provided Schema does not match Table [blah]"
      }
  }
  </code></pre>
  
  <p>With BQ tool I get following error:</p>
  
  <pre><code>./bq update -t blah added_column:integer
  </code></pre>
  
  <p><em>BigQuery error in update operation: Provided Schema does not match Table [blah]</em></p>