Why files in config directory in shared path are deleting when copying these files from shared path to release path using Capistrano?

Question

I am deploying a Dockerized Ruby on Rails application in AWS. I need to run the docker-compose commands on server via Capistrano script.

Scenario 1: When I am trying to run docker-compose build command after deploy.

namespace :deploy do
  task :docker_compose_build do
    on roles(:app, :web) do
      within release_path do
        execute "cd #{release_path} && docker-compose build"
      end
    end
  end
end
after "deploy", "deploy:docker_compose_build"

I am getting error "Invalid file database.yml" within docker image. Getting this error because Capistrano create symlink of linked_files instead copying.

Scenario 2: Removed database.yml from linked_files and trying to copy this file as below.

namespace :deploy do
  task :docker_prepare do
    on roles(:app) do
      within release_path do
        fetch(:config_files).each do |file|
          execute "cp #{shared_path}/config/#{file} #{release_path}/config/#{file}"
        end
      end
    end
  end

  task :docker_compose_build do
    on roles(:app, :web) do
      within release_path do
        execute "cd #{release_path} && docker-compose build"
      end
    end
  end
end
after "deploy:symlink:linked_files", "deploy:docker_prepare"
after "deploy", "deploy:docker_compose_build"

database.yml file is copying from shared path to release path but It is deleting from shared. I am not understanding why cp command is deleting the source file? Can anyone please help me to resolve my problem?