Environment
-----------

The following environment variables are set by default:

TODOs
-----

* Support installation-wide settings. Useful for shared environment
  settings etc (PATH).

* Add support for hooks in .app/hooks. Example hooks:
    * Diff config. Save a backup of the config On installtaion

* Support changing current version.

* Document app.sh
    * Concept: config. group, key and value.
    * Scriptable

Method Contract
---------------

### Environment variables you can depend on

* `APPSH_NAME`
* `APPSH_INSTANCE`
* `APPSH_METHOD`
* `APPSH_PID_FILE`