Add update methods for Coinbase and Bitstamp

Registered by mogray

Add update methods for Coinbase and Bitstamp.

Fetch URLs:

Coinbase: https://api.coinbase.com/v1/prices/spot_rate
Bitstamp: https://www.bitstamp.net/api/ticker/

Blueprint information

Status:
Not started
Approver:
None
Priority:
Undefined
Drafter:
mogray
Direction:
Needs approval
Assignee:
None
Definition:
New
Series goal:
Accepted for 0.7.5
Implementation:
Unknown
Milestone target:
None

Whiteboard

(?)

Work Items

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