I've got a virtual server (Digital Ocean Droplet) set up with Capistrano 3. I've successfully gotten all of the directories set up and the project directory has the current folder in it, containing config/database.yml file. I can't get it deployed to where it will run. It gets stuck on the rake db:migrate phase. rake assets:precompile successfully works, so I think it must be something with my database.yml file. The "production" block looks like this:

*config/database.yml (production part)
*

production:
  adapter: mysql2
  encoding: utf8
  database: capstone_production
  username: <%= ENV['DATABASE_USERNAME'] %>
  password: <%= ENV['DATABASE_PASSWORD'] %>
  host: localhost
  port: /var/run/mysqld/mysqld.sock

I have checked that the file is valid YAML with YAMLLint utility. Also, the environment variables echo properly with (root) credentials that I am able to use for mysql login. When I run cap production deploy:check, everything is good. However, running cap production deploy does everything okay until it gets to the rake db:migrate Capistrano process. Then it aborts and throws up this:

The deploy has failed with an error: #<SSHKit::Runner::ExecuteError: Exception while executing on host 107.170.105.223: Exception while executing on host 107.170.105.223: rake exit status: 1
rake stdout: rake aborted!
Mysql2::Error: Access denied for user 'root'@'localhost' (using password: NO)
/home/deploy/apps/capstone_project/shared/bundle/ruby/2.1.0/gems/mysql2-0.3.20/lib/mysql2/client.rb:70:in `connect'
/home/deploy/apps/capstone_project/shared/bundle/ruby/2.1.0/gems/mysql2-0.3.20/lib/mysql2/client.rb:70:in `initialize'
/home/deploy/apps/capstone_project/shared/bundle/ruby/2.1.0/bundler/gems/rails-331210df7c8a/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb:18:in `new'
/home/deploy/apps/capstone_project/shared/bundle/ruby/2.1.0/bundler/gems/rails-331210df7c8a/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb:18:in `mysql2_connection'
/home/deploy/apps/capstone_project/shared/bundle/ruby/2.1.0/bundler/gems/rails-331210df7c8a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb:435:in `new_connection'
/home/deploy/apps/capstone_project/shared/bundle/ruby/2.1.0/bundler/gems/rails-331210df7c8a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb:445:in `checkout_new_connection'
/home/deploy/apps/capstone_project/shared/bundle/ruby/2.1.0/bundler/gems/rails-331210df7c8a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb:416:in `acquire_connection'
/home/deploy/apps/capstone_project/shared/bundle/ruby/2.1.0/bundler/gems/rails-331210df7c8a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb:351:in `block in checkout'
/home/deploy/apps/capstone_project/shared/bundle/ruby/2.1.0/bundler/gems/rails-331210df7c8a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb:350:in `checkout'
/home/deploy/apps/capstone_project/shared/bundle/ruby/2.1.0/bundler/gems/rails-331210df7c8a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb:265:in `block in connection'
/home/deploy/apps/capstone_project/shared/bundle/ruby/2.1.0/bundler/gems/rails-331210df7c8a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb:264:in `connection'
/home/deploy/apps/capstone_project/shared/bundle/ruby/2.1.0/bundler/gems/rails-331210df7c8a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb:541:in `retrieve_connection'
/home/deploy/apps/capstone_project/shared/bundle/ruby/2.1.0/bundler/gems/rails-331210df7c8a/activerecord/lib/active_record/connection_handling.rb:113:in `retrieve_connection'
/home/deploy/apps/capstone_project/shared/bundle/ruby/2.1.0/bundler/gems/rails-331210df7c8a/activerecord/lib/active_record/connection_handling.rb:87:in `connection'
/home/deploy/apps/capstone_project/shared/bundle/ruby/2.1.0/bundler/gems/rails-331210df7c8a/activerecord/lib/active_record/migration.rb:916:in `initialize'
/home/deploy/apps/capstone_project/shared/bundle/ruby/2.1.0/bundler/gems/rails-331210df7c8a/activerecord/lib/active_record/migration.rb:814:in `new'
/home/deploy/apps/capstone_project/shared/bundle/ruby/2.1.0/bundler/gems/rails-331210df7c8a/activerecord/lib/active_record/migration.rb:814:in `up'
/home/deploy/apps/capstone_project/shared/bundle/ruby/2.1.0/bundler/gems/rails-331210df7c8a/activerecord/lib/active_record/migration.rb:792:in `migrate'
/home/deploy/apps/capstone_project/shared/bundle/ruby/2.1.0/bundler/gems/rails-331210df7c8a/activerecord/lib/active_record/railties/databases.rake:34:in `block (2 levels) in <top (required)>'
Tasks: TOP => db:migrate
(See full trace by running task with --trace)
rake stderr: Nothing written

I've tried many combinations of YAML syntax and restarted mysql server, puma server, and NGINX server over and over again. This is crazy, please help.

Thank you