let services specify their schemas in code.

lib/service.rb

@@ -32,6 +32,93 @@ def receive(event, data, payload = nil)
       end
     end
 
+    # Gets the current schema for the data attributes that this Service
+    # expects.  This schema is used to generate the GitHub repository admin
+    # interface.  The attribute types loosely to HTML input elements.
+    #
+    # Example:
+    #
+    #   class FooService < Service
+    #     string :token
+    #   end
+    #
+    #   FooService.schema
+    #   # => [[:string, :token]]
+    #
+    # Returns an Array of [Symbol, String] tuples.
+    def schema
+      @schema ||= []
+    end
+
+    # Public: Adds the given attributes as String attributes in the Service's
+    # schema.
+    #
+    # Example:
+    #
+    #   class FooService < Service
+    #     string :token
+    #   end
+    #
+    #   FooService.schema
+    #   # => [[:string, :token]]
+    #
+    # *attrs - Array of Symbol attribute names.
+    #
+    # Returns nothing.
+    def string(*attrs)
+      add_to_schema :string, attrs
+    end
+
+    # Public: Adds the given attributes as Password attributes in the Service's
+    # schema.
+    #
+    # Example:
+    #
+    #   class FooService < Service
+    #     password :token
+    #   end
+    #
+    #   FooService.schema
+    #   # => [[:password, :token]]
+    #
+    # *attrs - Array of Symbol attribute names.
+    #
+    # Returns nothing.
+    def password(*attrs)
+      add_to_schema :password, attrs
+    end
+
+    # Public: Adds the given attributes as Boolean attributes in the Service's
+    # schema.
+    #
+    # Example:
+    #
+    #   class FooService < Service
+    #     boolean :digest
+    #   end
+    #
+    #   FooService.schema
+    #   # => [[:boolean, :digest]]
+    #
+    # *attrs - Array of Symbol attribute names.
+    #
+    # Returns nothing.
+    def boolean(*attrs)
+      add_to_schema :boolean, attrs
+    end
+
+    # Adds the given attributes to the Service's data schema.
+    #
+    # type  - A Symbol specifying the type: :string, :password, :boolean.
+    # attrs - Array of Symbol attribute names.
+    #
+    # Returns nothing.
+    def add_to_schema(type, attrs)
+      attrs.each do |attr|
+        schema << [type, attr.to_sym]
+      end
+    end
+
     # Gets the String name that identifies this Service type.
     #
     # Returns a String.