Add Make A String Attribute Easy To Inquire About as a Rails TIL

rails/make-a-string-attribute-easy-to-inquire-about.md

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+# Make A String Attribute Easy to Inquire About
+
+Have you ever been curious why Rails environment checks work the way they do?
+
+```ruby
+> Rails.env
+#=> 'development'
+> Rails.env.development?
+#=> true
+```
+
+What is powering this is
+[`ActiveSupport::StringInquirer`](https://api.rubyonrails.org/classes/ActiveSupport/StringInquirer.html).
+And since it is part of `ActiveSupport`, you can use that functionality
+elsewhere in your Rails code.
+
+Let's look at an example:
+
+```ruby
+class UserWithRole
+  attr_reader :name, :role
+
+  def initialize(name, role)
+    @name = name
+    @role = ActiveSupport::StringInquirer.new(role)
+  end
+end
+```
+
+With that class defined, we can initialize a user and inquire about their role.
+
+```ruby
+> user = UserWithRole.new('Bob', 'instructor')
+#=> <UserWithRole ...>
+> user.role.instructor?
+#=> true
+> user.role.admin?
+#=> false
+> user.role
+#=> 'instructor'
+```
+
+This helper class makes it much cleaner to inquire about the role of a user.
+Notice we don't have to do a string comparison to check if they are an
+instructor, e.g.:
+
+```ruby
+> user.role == 'instructor'
+```