Jihoon Lee

The player's racket can get out of the table when keep pressing on the same direction.

This PR adds `bigdecimal` as a dependency in the `liquid` gemspec file. While using Ruby 3.3.0, I encountered this warning related to the `liquid` package. `/Users/my_name/.gem/ruby/3.3.0/gems/liquid-4.0.4/lib/liquid/standardfilters.rb:2: warning: bigdecimal was loaded...