Install PostgreSQL 9.3 on Semaphore

pg_9.3.sh

sudo apt-get -y remove postgresql-9.4 postgresql-contrib-9.4 postgresql-client-9.4 postgresql-server-dev-9.4
wget --quiet -O - http://apt.postgresql.org/pub/repos/apt/ACCC4CF8.asc | sudo apt-key add -
echo " deb http://apt.postgresql.org/pub/repos/apt/ precise-pgdg main" | sudo tee -a /etc/apt/sources.list
sudo apt-get update
sudo apt-get -y --force-yes install postgresql-client-9.3 postgresql-9.3 postgresql-contrib-9.3 postgresql-server-dev-9.3
sudo su - postgres -c "pg_dropcluster --stop 9.3 main"
sudo su - postgres -c "pg_createcluster --start -e UTF-8 9.3 main"
sudo su - postgres -c "psql -c \"CREATE USER runner WITH PASSWORD 'semaphoredb';\" -d template1"
sudo su - postgres -c "psql -c \"ALTER USER runner CREATEUSER CREATEDB;\" -d template1"
sudo service postgresql start || true

Downgrade postgresql on Semaphore to 9.3 with command like:
cd ~ && wget https://gist.github.com/rastasheep/6fb1cefa4f67793c0c29/raw/ddea20d9692583713829bb2c4af0878b43c0bb11/pg_9.3.sh && bash pg_9.3.sh && cd -