Can't install the package

[onurcanbektas]

When I add the mentioned section to the stack.yaml, I get the following error

YAML parse exception at line 73, column 0,
while scanning a simple key:
could not find expected ':'
See http://docs.haskellstack.org/en/stable/yaml_configuration/

[onurcanbektas]

Guys, I think you have started an amazing project and I want this project to be continued, so I want to contribute and use this project, but first I need to install & see it how it is working.