check how to install newrelic on php image?
check how to install blackfire
check php modules duplicate loading
add a way to configure service dependencies by ENV var So e.g. we support launching crond / jenkins / phpfpm after we can reach the given addresses. Possible map syntax: smtp.my.domain:2525/600 where the 600 specifies an optional timeout in seconds. Default timeout should be 600.
add a way to configure an alternate phpfpm IP address Required for docker-compose environemnts, so phpfpm can be accessed by its service name; instead of looking at 127.0.0.1. Check if we need to configure a nginx resolver for this to work?
integrate php phan checks in test section - https://github.com/phan/phan
add php linting test
add a generic netrc BUILD_ARG in ONBUILD, to support even more scenarios
add opencensus PHP extension + docs about how to integrate it
add NPM_CONFIG_REGISTRY support (and docs about how to use your own npm registry); same for composer (via ONBUILD)
document how to extend php ini with own files
docuemnt how to extend nginx config
renumber steps with more room for injections

Examples

Minor versions

add generic args to support github / gitlab / bitbucket netrc auto-generation (and mark gitlab args as deprecated)