Adding a new env to handle escalating privileges to run db migrations.

(cherry picked from commit d2554909d8)

lms/envs/aws_migrate.py

@@ -0,0 +1,8 @@
+from .aws import *
+import os
+
+USER = os.environ.get('DB_MIGRATION_USER', 'root')
+PASSWORD = os.environ.get('DB_MIGRATION_PASS', None)
+
+DATABASES['default']['USER'] = USER
+DATABASES['default']['PASSWORD'] = PASSWORD