The "tests" target fails in the custom directory

[panychek]

Due to the hardcoded image name (elastica_elastica) in the Makefile, the following won't work:

git clone https://github.com/ruflin/Elastica.git custom-directory
cd custom-directory
make tests

...
docker run -e "ES_HOST=elasticsearch" --network=elastica_esnet elastica_elastica make phpunit
Unable to find image 'elastica_elastica:latest' locally
docker: Error response from daemon: pull access denied for elastica_elastica, repository does not exist or may require 'docker login'.
See 'docker run --help'.
Makefile:60: recipe for target 'tests' failed
make: *** [tests] Error 125

Instead, the image named custom-directory_elastica is being created.