implement basic feature (#5)

* implement main.rb

* add comma

* remove space

* use Env#fetch

* use single quote

* use to_s

* fix raising error syntax

main.rb

@@ -0,0 +1,23 @@
+require 'net/http'
+
+params = {
+  token: ENV.fetch('API_TOKEN', nil),
+  room_id: ENV.fetch('ROOM_ID', nil),
+  user_ids: ENV.fetch('USER_IDS', nil),
+  body: ENV.fetch('BODY', nil).delete_prefix('"').delete_suffix('"')
+}
+
+uri = URI.parse("https://api.chatwork.com/v2/rooms/#{params[:room_id]}/tasks")
+http = Net::HTTP.new(uri.host, uri.port)
+http.use_ssl = true
+
+body = "body=#{params[:body]}&to_ids=#{params[:user_ids]}"
+headers = { 'X-ChatWorkToken' => params[:token].to_s }
+
+response = http.post(uri.path, body, headers)
+
+if response.code == '200'
+  puts response.body
+else
+  raise StandardError, "action failed! #{response.body}"
+end