Copyright 2008 Ken Collins, Decisiv Inc.
Distributed via MIT license
Feedback appreciated: kcollins at [nospam] decisiv dt net

This class greatly speeds up deploy times to multiple hosts by only updating your latest source code to a 
shared drive on a single host. If you have 5 app servers then the code update only happens with the primary 
or first server while all others use the shared cache to copy from. The remote cache is a SCM export 
created in one of the following two ways.

  1) If :remote_repository_access is not set or is false, a local export is made, compressed
     and copied to the target host and uncompressed to the remote shared cache.
  2) If :remote_repository_access returns true, the target host will perform a direct SCM 
     export to the remote shared cache.

Despite which method is used above, the creation of the remote shared cache will only target the primary 
app server using the primary_app_server() method. Again all other app targets assume that this is a 
shared directory accessbile to all. This yeilds faster deployments since capistrano does not have to 
locally prepare/compress/copy the source to each host.

This development strategy inherets from the normal Copy deployment strategy and uses many of the same 
metods/configurations available to that class when needing to perform local export and copy of the source.
Examples include, :copy_compression, :copy_remote_dir, :copy_dir. Configurations specific to this strategy 
includes, :shared_cache_dir (parent of all cached revisions) and :remote_repository_access (which determins 
what method is used above to create the shared cache).