Disable csrf for json

[alexeuler]

Disable CSRF for json requests to enable mobile requests to the API

---

This change is

[justin808]

@alleycat-at-git Next time please run inters:

rubocop -a                                                                                                                                                       [16:14:26]
Inspecting 41 files
..C......................................

Offenses:

app/controllers/application_controller.rb:4:46: C: [Corrected] Style/Proc: Use proc instead of Proc.new.
  protect_from_forgery with: :exception, if: Proc.new { request.headers['X-Auth'] != 'tutorial_secret' }
                                             ^^^^^^^^
app/controllers/application_controller.rb:4:73: C: [Corrected] Style/StringLiterals: Prefer double-quoted strings unless you need single quotes to avoid extra backslashes for escaping.
  protect_from_forgery with: :exception, if: Proc.new { request.headers['X-Auth'] != 'tutorial_secret' }
                                                                        ^^^^^^^^
app/controllers/application_controller.rb:4:86: C: [Corrected] Style/StringLiterals: Prefer double-quoted strings unless you need single quotes to avoid extra backslashes for escaping.
  protect_from_forgery with: :exception, if: Proc.new { request.headers['X-Auth'] != 'tutorial_secret' }
                                                                                     ^^^^^^^^^^^^^^^^^

41 files inspected, 3 offenses detected, 3 offenses corrected

[justin808]

---

Reviewed 1 of 1 files at r2.
Review status: 0 of 1 files reviewed at latest revision, all discussions resolved.

---

Comments from Reviewable