Add rules, conventions and suggestions.

[agerace]

• Use snake_case with JSON
• Don't use response envelopes by default
• Use all HTTP verbs ( Not everything is a GET )
• No, really, use them, and use them good. Semantic use of HTTP Verbs
• Use Nouns for endpoints names ( URLs )
• Plural Nouns vs. Singular Nouns ( /me => /users/:id )
• Pagination ( The rule breakers )
• Return something useful from POST, PATCH & PUT requests
• Right use of Status Codes
• Version via the headers, not via URL (SUGGESTION)
• Use query parameters for advanced filtering, sorting & searching
• Use JSON where possible, XML only if you have to
• Consider using JSON for POST, PUT and PATCH request bodies
• Define a consumable error payload
• Effectively use HTTP Status codes
• Use token based authentication, transported over OAuth2 where delegation is needed