Add ability for multiple counters that are RESTful

[rofrano]

As a: User
I need: the ability to create multiple RESTful counters
So that: I can keep track of multiple hit targets

Assumptions:

• We will implement using REST API guidelines
• Add ability to create multiple named counters
• Add ability to update counters by name

Tasks:

• Need to update root / URL to return json message
• Need to rename /counter to /counters
• Need to change GET to only return the counter
• Need to implemtent POST to create new counters
• Need to implement PUT to update multiple counters

Acceptance Criteria:

Given I have a multi-counter ability
When I create a counter named foo
And I update the counter named foo to 1
And I call the hit /counters/foo URL
Then I should see 1 returned from the service