Add simple upgrade script for deployments.

scripts/upgrade.sh

@@ -0,0 +1,31 @@
+#!/bin/bash
+set -o errexit
+
+# If we're not in a virtual environment and haven't passed "force" to the
+# script, then make sure the user wants to run the upgrade.
+if [[ (! $VIRTUAL_ENV)  && (! $1 || (! ($1 -neq 'force'))) ]]; then
+    read 'You are not running in a virtual environment, are you sure you would like to proceed? ' -n 1 -r
+    if [[ ! $REPLY =~ ^[Yy]$ ]]; then
+        echo 'Aborting upgrade.'
+        exit 1
+    fi
+fi
+
+echo Upgrading Cycledash
+echo
+echo Pulling from origin/master...
+git pull origin master
+
+echo Installing and upgrading dependencies...
+source ENV.sh
+pip install -r requirements.txt
+npm install
+
+echo Building assets...
+gulp prod
+
+echo Migrating the database...
+alembic upgrade head
+
+echo Done upgrading Cycledash.
+echo Restart workers and the Cycledash server to finish your upgrade.