change master branch

config/deploy/staging.rb

@@ -2,7 +2,7 @@ require 'json'
 file = File.read("config/server.json")
 deploy_config = JSON.parse(file)
 
-branch = deploy_config['branch'] || 'master'
+branch = 'master'
 set :branch, branch
 
 append :linked_files, 'config/server.json'
@@ -12,6 +12,7 @@ set :rails_env, :production
 set :port, 40022
 set :repo_url, 'ssh://gitlab@gitlab.ikcrm.com:40022/ikcrm_server/app_push.git'
 set :application, 'app_push'
+set :rvm_ruby_version, '2.6.5'
 
 set :deploy_to, deploy_config['deploy_to']
 set :shared_path, -> { fetch(:deploy_to) + '/shared' }