Dockerize development environment

Add a Dockerfile that can be used to build a development environment for
Seastar. This is useful for people such as myself who don't want to
install packages from Rawhide on my main development machine.

Steps to use it on Fedora:

1. Install Docker: http://docs.docker.com/installation/fedora/

  $ sudo yum install docker-io

  $ sudo systemctl start docker

  $ sudo systemctl enable docker

  [ Note: I had to edit /etc/sysconfig/docker to disable SELinux support
    because I use BTRFS. ]

2. Build a Docker image:

  $ docker build -t seastar-dev .

3. Launch a Docker instance:

  [ Seastar git repository is located in $HOME/seastar on the host. ]

  $ docker run -v $HOME/seastar/:/seastar -i -t seastar-dev /bin/bash

4. Build Seastar:

  $ cd /seastar
  $ make

5. Run an application:

  $ ./build/release/apps/httpd/httpd

Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

Dockerfile

@@ -0,0 +1,5 @@
+FROM fedora
+
+RUN yum install -y fedora-release-rawhide
+RUN yum --enablerepo rawhide install -y gcc-c++ libasan libubsan
+RUN yum install -y make python3 gperftools-devel libaio-devel ninja-build boost-devel git

README.md

@@ -31,6 +31,27 @@ Then finally:
 make
 ```
 
+### Building seastar in Docker container
+
+To build a Docker image:
+
+```
+docker build -t seastar-dev .
+```
+
+To launch a container:
+
+```    
+$ docker run -v $HOME/seastar/:/seastar -i -t seastar-dev /bin/bash
+```
+
+Finally, to build seastar inside the container:
+
+```    
+cd /seastar
+make
+```
+
 Futures and promises
 --------------------