docker: copy project files in Docker image

- adds he entire project files in the Dockerfile.base, needed by the cmd
  pipenv install which is installing the local Python package in
  editable mode
- closes inveniosoftware#244

{{cookiecutter.project_shortname}}/Dockerfile.base

@@ -8,5 +8,5 @@
 # Invenio usually needs.
 
 FROM inveniosoftware/centos7-python:3.6
-COPY Pipfile Pipfile.lock ./
+COPY ./ .
 RUN pipenv install --deploy --system