[Rails] Load environment variables from file `config/local_env.yml`. Place file in `config/initializers/`

load_environment_variables.rb

# Loads environment variables from file config/local_env.yml
# access vars using ENV['VAR_NAME']

env_file = File.join(Rails.root, 'config', 'local_env.yml')
if File.exists?(env_file)
    YAML.load(File.open(env_file)).each do |key, value|
        ENV[key.to_s] = value
    end
end