Consolidate readme/wiki docs into organized docs folder

docs/upgrading.md

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+# Upgrading
+
+Dokku is in active development. You can update the deployment step and the build step separately.
+
+**Note**: If you are upgrading from a revision prior to [27d4bc8c3c](https://github.com/progrium/dokku/commit/27d4bc8c3c19fe580ef3e65f2f85b85101cd83e4), follow the instructions in [this wiki entry](https://github.com/progrium/dokku/wiki/Migrating-to-Dokku-0.2.0).
+
+To update the deploy step (this is updated less frequently):
+
+```bash
+cd ~/dokku
+git pull origin master
+sudo make install
+```
+
+Nothing needs to be restarted. Changes will take effect on the next push / deployment.
+
+To update the build step:
+
+```bash
+git clone https://github.com/progrium/buildstep.git
+cd buildstep
+git pull origin master
+sudo make build
+```
+
+This will build a fresh Ubuntu Quantal image, install a number of packages, and
+eventually replace the Docker image for buildstep.
+
+## Migrating from 0.1.0 to 0.2.0
+
+This should be summary of breaking changes between 0.1 and 0.2 version with instructions to upgrade.
+
+### software-properties-common
+
+software-properties-common is now dependency for plugins. Before running dokku install script, make sure it installed.
+
+```bash
+> sudo apt-get install software-properties-common
+```
+
+### Gitreceive removed
+
+PR [#270](https://github.com/progrium/dokku/pull/270).
+
+Starting with Dokku 0.2.0, [Gitrecieve](https://github.com/progrium/gitreceive) is replaced by a `git`plugin.
+
+Dokku no longer uses the `git` user. Everything is done with the `dokku` user account.
+
+This causes the remote url to change. Instead of pushing to `git@hostname:app`, you should now push to `dokku@hostname:app`.
+The url must be modified using the `git remote set-url` command :
+
+    git remote set-url deploy dokku@hostname:app
+
+Where `deploy` is the name of the remote.
+
+Additionally, the repositiories on the server must be migrated to work with dokku 0.2.0
+
+There is upgrade [script](https://gist.github.com/plietar/7201430), which is meant to automate this migration. To use it:
+
+1. run the script as root
+2. `git pull` to get the latest version of dokku
+3. make install
+4. `dokku deploy:all`
+
+TDB.
+
+### Cache directory
+
+Commit [#6350f373](https://github.com/progrium/dokku/commit/6350f373be2cef4f3bb90912099e1be6196522d1)
+
+Buildstep have to re-installed in order to support cache directory.
+
+TDB.