Preserve cache directory between builds

HISTORY.md

@@ -2,6 +2,7 @@
 
 ## 0.2.0 (in progress)
 
+* Cache dir is preserved across builds
 * Application config (environment variable management)
 * Basic hooks/plugin system
 * Exposed commands over SSH using sshcommand
@@ -17,4 +18,4 @@
    * Bootstrap script for Ubuntu system
    * Basic push / deploy with git
    * Hostname support with Nginx
-   * Support for Java, Ruby, Node.js buildpacks
+   * Support for Java, Ruby, Node.js buildpacks