Add MDS Metrics API spec

[whereissean]

MDS Pull Request

Explain pull request

This PR represents a proposal for a standard interface for historical MDS metrics and data aggregation.

Is this a breaking change

• No, not breaking

Impacted Spec

• agency
• provider

Additional context

This PR is related to the MDS Metrics Issue #485.

[CLAassistant]

All committers have signed the CLA.

[jfh01]

Suggested change

	| `interval` | duration | Yes | Duration for metrics intervals. |
	| `interval` | duration | Yes | ISO 8601 formatted duration for metrics intervals. |

[schnuerle]

Note that for 1.1.0 we have merged with #582 the new Geography API to the 'dev' branch. Please update this pull request with the latest code, resolve any conflicts, and make references to the Geography API where appropriate, e.g. with UUIDs.

We will be discussing Metrics at this week's Working Group meeting, so if available please come prepared to talk about your latest updates and ideas.

[schnuerle]

Leaving a comment here from #123 (now closed in favor of this PR). Wanted info on subscribers and low_income riders. Could be part of #569 too.

membership_type
subscriber
subscriber_low_income
single_ride
single_ride_low_income

[schnuerle]

Leaving a comment here from #76 (now closed in favor of this PR). Wanted info on access methods. Could be part of #569 too.

access_method	meaning
qr_code	The user scanned a QR code with their mobile device
keypad	The user entered an identification number on a keypad
transit_card	The user used a transit card to unlock the vehicle
rfid	The user accessed the vehicle with an RFID card or fob that is not a transit card
mobile_id	The user entered the ID of the device on their mobile phone
other_mobile	The user used a mobile phone, but did not scan a QR code or enter a vehicle ID
credit_card_pay	The user swiped/inserted/tapped their credit card to pay for the ride
credit_card_id	The user swiped/inserted/tapped their credit card to identify themselves, but their card was not charged an additional amount
cash_attendant	The user paid an attendant or operator cash to use the vehicle
cash_automated	The user paid cash using an automated system
call_center	The user accessed the vehicle by calling a call center operated by humans
ivr	An interactive voice response system was used to access the vehicle
sms	An SMS system was used to access the vehicle
no_security	The vehicles are unsecured and can be used by anyone without charge

[schnuerle]

I've made a feature branch called 'feature-metrics' to start pulling all the Metrics related work together and do PRs against. Updated this PR to point to that instead of 'dev'.

[schnuerle]

Closing this since the entire PR was incorporated into #487 for review and before merger to the Metrics feature branch.