Get transactions (#45)

* Make transactions requests in parallel

* Update transaction error handling

scripts/install-postgres-10.sh

@@ -0,0 +1,17 @@
+#!/usr/bin/env bash
+# Travis doesn't support postgres 10
+# https://github.com/travis-ci/travis-ci/issues/8537
+
+set -ex
+
+echo "Installing Postgres 10"
+sudo service postgresql stop
+sudo apt-get remove -q 'postgresql-*'
+sudo apt-get update -q
+sudo apt-get install -q postgresql-10 postgresql-client-10
+sudo cp /etc/postgresql/{9.6,10}/main/pg_hba.conf
+
+echo "Restarting Postgres 10"
+sudo service postgresql restart
+
+sudo psql -c 'CREATE ROLE travis SUPERUSER LOGIN CREATEDB;' -U postgres