Build assets before running migrations

The migrations now fail with `BrandableCSS::DefaultMD5NotUpToDateError`
if you try to run them before building assets. This commit updates the
docker_dev_setup.sh script to build assets first to avoid this error.

Also updates the script to use the correct docker package: `docker` in
the Ubuntu package repos is actually some kind of system tray thing. We
want the `docker.io` package:
https://packages.ubuntu.com/xenial/docker.io

Refs instructuregh-1300

Change-Id: Iba9a6f9bffe1a9e60bd715f1214caaab0394d37e
Reviewed-on: https://gerrit.instructure.com/150865
Reviewed-by: Ryan Shaw <[email protected]>
Tested-by: Jenkins
Product-Review: Omar Khan <[email protected]>
QA-Review: Omar Khan <[email protected]>

script/docker_dev_setup.sh

@@ -41,7 +41,7 @@ if [[ $OS == 'Darwin' ]]; then
   dependencies='docker docker-machine docker-compose dinghy'
 elif [[ $OS == 'Linux' ]]; then
   install='sudo apt-get update && sudo apt-get install -y'
-  dependencies='docker docker-compose'
+  dependencies='docker.io docker-compose'
 else
   echo 'This script only supports MacOS and Linux :('
   exit 1
@@ -258,8 +258,8 @@ function setup_canvas {
   copy_docker_config
   build_images
   install_gems
-  prepare_database
   compile_assets
+  prepare_database
 }
 
 function display_next_steps {