Update docker instructions (#295)

installation/single_machine_docker.rst

@@ -5,24 +5,44 @@ Docker
 
 This section describes setting up a Citus cluster on a single machine using docker-compose.
 
-**1. Install docker and docker-compose**
+1. Install Docker Engine and docker-compose
+-------------------------------------------
 
-Follow the installation instructions for `Docker Engine <https://docs.docker.com/engine/installation/>`_ and `Docker Compose <https://docs.docker.com/compose/install/>`_ on your platform.
+Mac
+~~~
 
-**2. Start the Citus Cluster**
+* Install the `Docker Platform <https://www.docker.com/products/overview#/install_the_platform>`_.
+* Start Docker by clicking on the application's icon.
+
+Linux
+~~~~~
+
+.. code-block:: bash
+
+  curl -sSL https://get.docker.com/ | sudo bash
+  sudo usermod -aG docker $USER && newgrp docker
+  sudo systemctl start docker
+
+  sudo curl -L https://github.com/docker/compose/releases/download/1.11.1/docker-compose-`uname -s`-`uname -m` -o /usr/local/bin/docker-compose
+  sudo chmod +x /usr/local/bin/docker-compose
+
+(This docker-compose version is fine for running Citus, or you can install the latest version by following instructions `here <https://github.com/docker/compose/releases/latest>`_.)
+
+2. Start the Citus Cluster
+--------------------------
 
 Citus uses docker-compose to run and connect containers holding the database master node, workers, and a persistent data volume. To create a local cluster download our docker-compose configuration file and run it
 
 .. code-block:: bash
 
-  wget https://raw.githubusercontent.com/citusdata/docker/master/docker-compose.yml
+  curl -L https://raw.githubusercontent.com/citusdata/docker/master/docker-compose.yml > docker-compose.yml
   docker-compose -p citus up -d
 
 The first time you start the cluster it builds its containers. Subsequent startups take a matter of seconds.
 
 .. note::
 
-  If you have PostgreSQL running on your machine you may encounter this error when starting the Docker containers:
+  If you already have PostgreSQL running on your machine you may encounter this error when starting the Docker containers:
 
   .. code::
 
@@ -36,8 +56,8 @@ The first time you start the cluster it builds its containers. Subsequent startu
     - ports: ['5432:5432']
     + ports: ['5433:5432']
 
-**3. Verify that installation has succeeded**
-
+3. Verify that installation has succeeded
+-----------------------------------------
 
 To verify that the installation has succeeded we check that the master node has picked up the desired worker configuration. First start the psql shell on the master node:
 
@@ -56,7 +76,8 @@ You should see a row for each worker node including the node name and port.
 Once you have the cluster up and running, you can visit our :ref:`multi-tenant tutorial <multi_tenant_tutorial>` to
 get started with a sample dataset on Citus in minutes.
 
-**4. Shut down the cluster when ready**
+4. Shut down the cluster when ready
+-----------------------------------
 
 When you wish to stop the docker containers, use docker-compose: