Add a method to send a photo.

src/telepathy/bot.cr

@@ -58,6 +58,41 @@ module Telepathy
                              body: message_data.to_json)
         end
 
+        def send_photo(chat_id : String | Int64, photo : String | File, caption : String? = nil,
+                       disable_notification : Bool = false,
+                       reply_to_message_id : Int64? = nil)
+            IO.pipe do |reader, writer|
+                channel = Channel(String).new(1)
+                spawn do
+                    HTTP::FormData.build(writer) do |formdata|
+                        channel.send(formdata.content_type)
+                        case chat_id
+                        when String
+                            formdata.field("chat_id", chat_id.as(String))
+                        when Int64
+                            formdata.field("chat_id", chat_id.as(Int64).to_s)
+                        end
+                        formdata.field("disable_notification", disable_notification.to_s)
+                        caption.try { |caption| formdata.field("caption", caption) }
+                        reply_to_message_id.try { |id| formdata.field("reply_to_message_id", id) }
+                        case photo
+                        when String
+                            formdata.field("photo", photo.as(String))
+                        when File
+                            formdata.file("photo", photo.as(IO),
+                                          HTTP::FormData::FileMetadata.new(filename: File.basename(photo.path)))
+                        end
+                    end
+
+                    writer.close
+                end
+
+                response = HTTP::Client.get(@request_base + "/sendPhoto",
+                                 headers: HTTP::Headers{"User-agent" => "Telepathy", "Content-type" => channel.receive },
+                                 body: reader)
+            end
+        end
+
         def command(command_name, &block: Update, Array(String) -> Void)
             @command_hooks[command_name] = block
         end