[For browser apps this happens in the window]
    Request: GET /get_authorization_code
                    ?response_type=code
                    &client_id={CLIENT_ID}
                    &redirect_uri={REDIRECT_URI}
                    [&state={STATE}]
                    [&scope={SCOPE}]

    Response: HTTP 302
                Location={REDIRECT_URI}
                    ?code={CODE}
                    &state={STATE}

    Error Response: HTTP 302
                Location={REDIRECT_URI}
                    ?error=access_denied
                    &state={STATE}

    [Server side only]
    Request: GET /get_access_token
                    ?grant_type=authorization_code
                    &client_id={CLIENT_ID}
                    &client_secret={CLIENT_SECRET}
                    &redirect_uri={REDIRECT_URI}
                    &code={CODE}

    Response: HTTP 200
                {
                   "access_token": "{ACCESS_TOKEN}",
                   "token_type": "{TOKEN_TYPE}",      // See OAuth 2 Section 7.1 Access Token Types
                   "expires_in": 3600,
                   "refresh_token": "{REFRESH_TOKEN}"
                 }

    Error Response: HTTP 400
                {
                    "error": "access_denied",
                    "error_description": "User does not have access to the team."
                }