Upgrade json-schema dependency to 2.7 (#50)
Upgrade json-schema dependency to 2.7 (#50)

Since `addressable` is a widely used dependency today and `json-schema 2.6` has it locked to `2.3` it becomes more difficult to resolve dependency conflicts with Bundler.

Upgrading `json-schema` to `2.7` will result in `addressable >= 2.4` dependency thus should ease up such dependency conflict resolutions.
seanpdoyle/json-matchers,thoughtbot/json_matchers