install.packages error

[traddo]

An error occurred when the package was installed according to the steps in the README.
`

curl_download('https://github.com/systematicinvestor/SIT/raw/master/SIT.tar.gz', 'sit',mode = 'wb',quiet=T)
install.packages('sit', repos = NULL, type='source')
ERROR: dependency ‘SIT.date’ is not available for package ‘SIT’
removing ‘/Library/Frameworks/R.framework/Versions/3.4/Resources/library/SIT’
Warning in install.packages :
installation of package ‘sit’ had non-zero exit status`

[traddo]

sorry, For my reasons, I didn't install devtools::install_github('systematicinvestor/SIT.date')