Add svc perms migration script and update readme

migrations/versions/0086_migrate_default_svc_perms.py

@@ -0,0 +1,28 @@
+"""empty message
+
+Revision ID: 0086_migrate_default_svc_perms
+Revises: 0085_update_incoming_to_inbound
+Create Date: 2017-05-23 18:13:03.532095
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = '0086_migrate_default_svc_perms'
+down_revision = '0085_update_incoming_to_inbound'
+
+from alembic import op
+import sqlalchemy as sa
+
+
+def upgrade():
+    def get_values(permission):
+        return "SELECT id, '{0}' FROM services WHERE "\
+            "id NOT IN (SELECT service_id FROM service_permissions "\
+            "WHERE service_id=id AND permission='{0}')".format(permission)
+
+    op.execute("INSERT INTO service_permissions (service_id, permission) {}".format(get_values('sms')))
+    op.execute("INSERT INTO service_permissions (service_id, permission) {}".format(get_values('email')))
+
+
+def downgrade():
+    op.execute("DELETE FROM service_permissions WHERE created_at IS NULL")