How do I fix my docker-compose.yml , error in installing Mayan-EDMS with django

I am trying to install the Mayan-EDMS image with the Django app and Postgres database using docker-compose but each time, I try to build docker-compose using docker-compose up it gives an error.

ERROR: yaml.parser.ParserError: while parsing a block mapping
  in "./docker-compose.yml", line 8, column 3
expected <block end>, but found