class ActiveRecord::DatabaseConfigurations::UrlConfig

connections.
database adapter, name, and other important information for database
* :config - The config hash. This is the hash that contains the
* :url - The database URL.
used in the second tier, for example “primary_readonly”.
database three-tier database configuration this corresponds to the name
database configuration this will default to “primary”. In a multiple
* :name - The db config name. In a standard two-tier
* :env_name - The Rails environment, i.e. “development”.
==== Options
@url=“postgres://localhost/foo”>
@config={adapter: “postgresql”, database: “foo”, host: “localhost”},
@env_name=“default_env”, @name=“primary”,
#<ActiveRecord::DatabaseConfigurations::UrlConfig:0x00007fdc3238f340
Becomes:
postgres://localhost/foo
A URL config:
or a hash with a URL in place of the config hash.
entry that is created from a URL. This can either be a URL string
A UrlConfig object is created for each database configuration

def build_url_hash

the passed in url
Return a Hash that can be merged into the main config that represents 
def build_url_hash
  if url.nil? || url.start_with?("jdbc:", "http:", "https:")
    { url: url }
  else
    ConnectionUrlResolver.new(url).to_hash
  end
end

def initialize(env_name, name, url, configuration_hash = {}) 

def initialize(env_name, name, url, configuration_hash = {})
  super(env_name, name, configuration_hash)
  @url = url
  @configuration_hash = @configuration_hash.merge(build_url_hash).freeze
end