Users that misconfigure their process's listening interface or port will now see an additional healthcheck warning for web deploys. While only a single port is checked, this ensures that users at least have some context as to why their app isn't responding as expected.
Closes#4798
This change converts existing CHECKS files into a healthchecks key that is understood by 'docker-container-healthchecker'. This tool supports a number of different types of container healthchecks - command, http, uptime - and can perform healthchecks against non-web processes.
The use of the old CHECKS file is now deprecated, and will be removed in the next minor version. Users can use the 'docker-container-healthchecker' to convert existing CHECKS files to the new format automatically.
Closes#2760
When developing Dokku, it is useful to use a real domain to test actual functionality. This is impossible if the domain is hardcoded to dokku.me in testing.
