Added information about django REST API to docs (#681)

* Django REST API documentation
* Additional volume
* Fixed link

README.md

@@ -13,6 +13,7 @@ CVAT is free, online, interactive video and image annotation tool for computer v
 
 - [Installation guide](cvat/apps/documentation/installation.md)
 - [User's guide](cvat/apps/documentation/user_guide.md)
+- [Django REST API documentation](#rest-api)
 - [XML annotation format](cvat/apps/documentation/xml_format.md)
 - [AWS Deployment Guide](cvat/apps/documentation/AWS-Deployment-Guide.md)
 - [Questions](#questions)
@@ -57,6 +58,11 @@ After you click the link above:
 
 If you have any questions, please contact Onepanel directly at support@onepanel.io. If you are in the Onepanel application, you can also use the chat icon in the bottom right corner.
 
+## REST API
+
+Automatically generated Swagger documentation for Django REST API is
+available on ``<cvat_origin>/api/swagger`` (default: ``localhost:8080/api/swagger``).
+
 ## LICENSE
 
 Code released under the [MIT License](https://opensource.org/licenses/MIT).
@@ -72,4 +78,4 @@ feel free to open an issue (with steps to reproduce the bug if it's a bug
 report).
 
 If you are not sure or just want to browse other users common questions,
-[Gitter chat](https://gitter.im/opencv-cvat) is the way to go.
+[Gitter chat](https://gitter.im/opencv-cvat) is the way to go.