2.0 New setting design

[huacnlee]

🚨 BREAK CHANGES WARNING: rails-settings-cached 2.x has redesign the API, the new version will compatible with the stored setting values by older version. But you must read the README.md again, and follow guides to change your Setting model.

• New design release.

• No more scope support (RailsSettings::Extend has removed);

• No more YAML file.

• You must use field method to statement the setting keys before use.

  For example:

  class Setting < RailsSettings::Base
    field :host, default: "http://example.com"
    field :readonly_item, type: :integer, default: 100, readonly: true
    field :user_limits, type: :integer, default: 1
    field :admin_emails, type: :array, default: %w[admin@rubyonrails.org]
    field :captcha_enable, type: :boolean, default: 1
    field :smtp_settings, type: :hash, default: {
      host: "foo.com",
      username: "foo@bar.com",
      password: "123456"
    }
  end

• One SQL or Cache hit in each request, even you has multiple of keys call in a page.

  NOTE: This design will load all settings from db/cache in memory, so I recommend that you do not design a lot of Setting keys (bellow 1000 keys), and do not save a large value in setting.

[codecov[bot]]

Codecov Report

Merging #158 into master will decrease coverage by 51.69%. The diff coverage is 37.5%.

@@            Coverage Diff            @@
##           master    #158      +/-   ##
=========================================
- Coverage   89.19%   37.5%   -51.7%     
=========================================
  Files          11       1      -10     
  Lines         361       8     -353     
=========================================
- Hits          322       3     -319     
+ Misses         39       5      -34

Impacted Files	Coverage Δ
test/models/setting.rb	37.5% <37.5%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more Δ = absolute <relative> (impact), ø = not affected, ? = missing data Powered by Codecov. Last update e842f7b...0cfce02. Read the comment docs.

[codecov[bot]]

Codecov Report

Merging #158 into master will increase coverage by 10.8%. The diff coverage is 100%.

@@           Coverage Diff            @@
##           master   #158      +/-   ##
========================================
+ Coverage   89.19%   100%   +10.8%     
========================================
  Files          11      1      -10     
  Lines         361      8     -353     
========================================
- Hits          322      8     -314     
+ Misses         39      0      -39

Impacted Files	Coverage Δ
test/models/setting.rb	100% <100%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more Δ = absolute <relative> (impact), ø = not affected, ? = missing data Powered by Codecov. Last update e842f7b...346ca38. Read the comment docs.