added ee update command

config/plugins.d/update.conf

@@ -0,0 +1,8 @@
+### Example Plugin Configuration for EasyEngine
+
+[update]
+
+### If enabled, load a plugin named `example` either from the Python module
+### `ee.cli.plugins.example` or from the file path
+### `/var/lib/ee/plugins/example.py`
+enable_plugin = true

ee/cli/plugins/update.py

@@ -0,0 +1,40 @@
+from cement.core.controller import CementBaseController, expose
+from cement.core import handler, hook
+from ee.core.download import EEDownload
+import time
+import os
+
+
+def ee_update_hook(app):
+    # do something with the ``app`` object here.
+    pass
+
+
+class EEUpdateController(CementBaseController):
+    class Meta:
+        label = 'ee_update'
+        stacked_on = 'base'
+        aliases = ['update']
+        aliases_only = True
+        stacked_type = 'nested'
+        description = ('update EasyEngine')
+        usage = "ee update"
+
+    @expose(hide=True)
+    def default(self):
+        filename = "eeupdate" + time.strftime("%Y%m%d-%H%M%S")
+        EEDownload.download(self, [["http://rt.cx/ee",
+                                    "/tmp/{0}".format(filename),
+                                    "EasyEngine update script"]])
+        try:
+            os.system("bash /tmp/{0}".format(filename))
+        except Exception as e:
+            Log.debug(self, e)
+            Log.error(self, "EasyEngine update failed !")
+
+
+def load(app):
+    # register the plugin class.. this only happens if the plugin is enabled
+    handler.register(EEUpdateController)
+    # register a hook (function) to run after arguments are parsed.
+    hook.register('post_argument_parsing', ee_update_hook)