feat(Interactions): Add support for button interactions (#62)

Exposes the "data" object which provides the custom_id of the clicked
button. Adds a convenience method for retrieving the selected button by
its custom_id, useful for obtaining the label of the clicked button.
Adds new buttony TYPES.

lib/discordrb/data/interaction.rb

@@ -7,7 +7,15 @@ class Interaction
     # @see https://discord.com/developers/docs/interactions/slash-commands#interaction-interactiontype
     TYPES = {
       ping: 1,
-      command: 2
+      command: 2,
+      button: 3
+    }.freeze
+
+    # Component types.
+    # @see https://discord.com/developers/docs/interactions/message-components#component-types
+    COMPONENT_TYPES = {
+      action_row: 1,
+      button: 2
     }.freeze
 
     # Interaction response types.
@@ -44,13 +52,17 @@ class Interaction
     # @see TYPES
     attr_reader :type
 
+    # @return [String] The interaction data.
+    attr_reader :data
+
     # @!visibility private
     def initialize(data, bot)
       @bot = bot
 
       @id = data['id'].to_i
       @application_id = data['application_id'].to_i
       @type = data['type']
+      @message = data['message']
       @data = data['data']
       @server_id = data['guild_id']&.to_i
       @channel_id = data['channel_id']&.to_i
@@ -175,6 +187,17 @@ def server
     def channel
       @bot.channel(@channel_id)
     end
+
+    # @return [Hash, nil] Returns the button that triggered this interaction if applicable, otherwise nil
+    def button
+      return unless @type == TYPES[:button]
+
+      @message['components'].each do |row|
+        row['components'].each do |component|
+          return component if component['type'] == COMPONENT_TYPES[:button] && component['custom_id'] == @data['custom_id']
+        end
+      end
+    end
   end
 
   # An ApplicationCommand for slash commands.