Sonarqube error : The main branch of this project is empty

Today I installed sonarqube and sonarqube runner to scan my php project . But after running the scanner it shows The main branch of this project is empty. .

#Configure here general information about the environment, such as SonarQube server connection details for example
#No information about specific project should appear here

#----- Default SonarQube server

#----- Default source code encoding

# --- optional properties ---

# defaults to project key
#sonar.projectName=My project
# defaults to 'not provided'
# Path is relative to the file. Defaults to .
# Encoding of the source code. Default is default system encoding

Can anyone tell me what am I doing wrong ? I want to test my php application using sonarqube

I just found this warning
SCM provider autodetection failed. Please use “sonar.scm.provider” to define SCM of your project, or disable the SCM Sensor in the project settings.

Could you please post your scanner logs?