basic ldap support (#842)

Dockerfile

@@ -3,7 +3,7 @@ RUN apt-get update
 RUN apt-get install -y make python-software-properties curl
 RUN curl -sL https://deb.nodesource.com/setup_7.x | bash -
 RUN apt-get update
-RUN apt-get install -y nodejs
+RUN apt-get install -y nodejs libldap2-dev libsasl2-dev libldap2-dev libssl-dev
 RUN pip install -U setuptools
 RUN pip install coveralls bandit
 WORKDIR /app