A couple rake tasks to back up and restore Postgres databases in Rails using your Rails Environment variable.

pg_backup.rake

namespace :db do
  desc "Runs pg_dump against the environment's database."
  task pg_dump: :environment do
    db_config = Rails.application.config.database_configuration[Rails.env]
    system "pg_dump -U #{db_config['username']} #{db_config['database']} -f dump_#{Rails.env}.sql"
  end

  desc "Loads a pg_dump file into the environment's database."
  task pg_restore: :environment do
    db_config = Rails.application.config.database_configuration[Rails.env]
    input = ''
    STDOUT.puts "Please provide the full path to the .sql backup file you want to restore:"
    input = STDIN.gets.chomp
    raise "File not found." unless File.exist?(input)
    system "psql -U #{db_config['username']} -d #{db_config['database']} -f #{input}"
  end
end