Added fluentd

Reordered compose commands to bring up graylog first and
added fluentd.

fluentd/Dockerfile

@@ -0,0 +1,9 @@
+FROM fluent/fluentd:v1.9.0-debian-1.0
+USER root
+RUN apt-get update \
+ && apt-get -y install --no-install-recommends wget \
+ && rm -rf /var/lib/apt/lists/*
+RUN gem install gelf
+RUN cd /fluentd/plugins \
+ && wget -q https://raw.githubusercontent.com/emsearcy/fluent-plugin-gelf/master/lib/fluent/plugin/out_gelf.rb
+COPY fluent.conf /fluentd/etc/

fluentd/fluent.conf

@@ -0,0 +1,11 @@
+<source>
+  @type forward
+  port 24224
+</source>
+
+<match **>
+  @type gelf
+  host vagrant_graylog_1
+  port 12201
+  flush_interval 5s
+</match>