fix readme.

Author: JVickery-TBS

README.md

@@ -65,7 +65,7 @@ To install ckanext-datastore-search:
   pip install -e .
 	pip install -r requirements.txt
   ```
-3. Add `development` to the `ckan.plugins` setting in your CKAN
+3. Add `datastore_search` to the `ckan.plugins` setting in your CKAN
    config file (by default the config file is located at
    `/etc/ckan/default/ckan.ini`).