doc: Updated README.md to include DremioExtractor (#379)

Signed-off-by: Josh Howard <josh.t.howard@ey.com>
Co-authored-by: Josh Howard <josh.t.howard@ey.com>

README.md

@@ -178,6 +178,23 @@ If using the filters option here is the input format
 ]
 ```
 
+#### [DremioMetadataExtractor](https://github.com/amundsen-io/amundsendatabuilder/blob/master/databuilder/extractor/dremio_metadata_extractor.py)
+An extractor that extracts table and column metadata including database, schema, table name, table description, column name and column description from [Dremio](https://www.dremio.com).
+
+Before running make sure that you have the Dremio ODBC driver installed. Default config values assume the default driver name for the [MacBook install](https://docs.dremio.com/drivers/mac-odbc.html).  
+```python
+job_config = ConfigFactory.from_dict({
+    'extractor.dremio.{}'.format(DremioMetadataExtractor.DREMIO_USER_KEY): DREMIO_USER,
+    'extractor.dremio.{}'.format(DremioMetadataExtractor.DREMIO_PASSWORD_KEY): DREMIO_PASSWORD,
+    'extractor.dremio.{}'.format(DremioMetadataExtractor.DREMIO_HOST_KEY): DREMIO_HOST})
+job = DefaultJob(
+	conf=job_config,
+	task=DefaultTask(
+		extractor=DremioMetadataExtractor(),
+		loader=AnyLoader()))
+job.launch()
+```
+
 #### [DruidMetadataExtractor](https://github.com/amundsen-io/amundsendatabuilder/blob/master/databuilder/extractor/druid_metadata_extractor.py)
 An extractor that extracts table and column metadata including database, schema, table name, table description, column name and column description from a [Druid](https://druid.apache.org/) DB.