Move all deployment methods into their own section

This makes our support for each method explicit, and also allows us to add more deployment methods in the future.

[ci skip]

docs/deployment/methods/buildpacks.md

@@ -0,0 +1,103 @@
+# Buildpack Deployment
+
+Dokku normally defaults to using [heroku buildpacks](https://devcenter.heroku.com/articles/buildpacks) for deployment, though this may be overridden by committing a valid `Dockerfile` to the root of your repository and pushing the repository to your Dokku installation. To avoid this automatic `Dockerfile` deployment detection, you may do one of the following:
+
+- Use `dokku config:set` to set the `BUILDPACK_URL` environment variable.
+- Add `BUILDPACK_URL` to a committed `.env` file in the root of your repository.
+  - See the [environment variable documentation](/dokku/configuration/environment-variables/) for more details.
+- Create a `.buildpacks` file in the root of your repository.
+
+## Specifying a custom buildpack
+
+In certain cases you may want to specify a custom buildpack. While dokku uses herokuish to support all the [official heroku buildpacks](https://github.com/gliderlabs/herokuish#buildpacks), it is possible that the buildpack detection does not work well for your application. As well, you may wish to use a custom buildpack to handle specific application logic.
+
+To use a specific buildpack, you can run the following dokku command:
+
+```shell
+# replace APP with the name of your application
+# replace REPOSITORY_URL with your buildpack's url
+dokku config:set APP BUILDPACK_URL=REPOSITORY_URL
+
+# example: using a specific ruby buildpack version
+dokku config:set APP BUILDPACK_URL=https://github.com/heroku/heroku-buildpack-ruby.git#v142
+```
+
+Please check the documentation for your particular buildpack as you may need to include configuration files (such as a Procfile) in your project root.
+
+## Using multiple buildpacks
+
+You can only set a single buildpack using the `BUILDPACK_URL`, though there may be times when you wish to use multiple buildpacks. To do so, simply create a `.buildpacks` file in the base of your repository. This file should list all the buildpacks, one-per-line. For instance, if you wish to use both the `nodejs` and `ruby` buildpacks, your `.buildpacks` file should contain the following:
+
+```shell
+https://github.com/heroku/heroku-buildpack-nodejs.git#v87
+https://github.com/heroku/heroku-buildpack-ruby.git#v142
+```
+
+> Always remember to pin your buildpack versions when using the multi-buildpacks method, or you may find deploys changing your deployed environment.
+
+You may also choose to set just a single buildpack in this file, though that is up to you.
+
+Please check the documentation for your particular buildpack(s) as you may need to include configuration files (such as a Procfile) in your project root.
+
+## Using a specific buildpack version
+
+As Dokku pins all buildpacks via herokuish releases, there may be occasions where a local buildpack version is out of date. If you wish to use a more recent version of the buildpack, you may use any of the above methods to specify a buildpack **without** the git sha attached like so:
+
+```shell
+# using the latest nodejs buildpack
+# replace APP with the name of your application
+dokku config:set APP BUILDPACK_URL=https://github.com/heroku/heroku-buildpack-nodejs
+```
+
+You may also wish to use a **specific** version of a buildpack, which is also simple
+
+```shell
+# using v87 of the nodejs buildpack
+# replace APP with the name of your application
+dokku config:set APP BUILDPACK_URL=https://github.com/heroku/heroku-buildpack-nodejs#v87
+```
+
+## Specifying commands via Procfile
+
+While many buildpacks have a default command that is run when a detected repository is pushed, it is possible to override this command via a Procfile. A Procfile can also be used to specify multiple commands, each of which is subject to process scaling. See the [process scaling documentation](/dokku/deployment/process-management/) for more details around scaling individual processes.
+
+A Procfile is a file named `Procfile`. It should be named `Procfile` exactly, and not anything else. For example, `Procfile.txt` is not valid. The file should be a simple text file.
+
+The file must be placed in the root directory of your application. It will not function if placed in a subdirectory.
+
+If the file exists, it should not be empty, as doing so may result in a failed deploy.
+
+The syntax for declaring a `Procfile` is as follows. Note that the format is one process type per line, with no duplicate process types.
+
+```
+<process type>: <command>
+```
+
+If, for example, you have multiple queue workers and wish to scale them separately, the following would be a valid way to work around the requirement of not duplicating process types:
+
+```Procfile
+worker:           env QUEUE=* bundle exec rake resque:work
+importantworker:  env QUEUE=important bundle exec rake resque:work
+```
+
+The `web` process type holds some significance in that it is the only process type that is automatically scaled to `1` on the initial application deploy. See the [process scaling documentation](/dokku/deployment/process-management/) for more details around scaling individual processes.
+
+## Clearing buildpack cache
+
+Building containers with buildpacks currently results in a persistent `cache` directory between deploys. If you need to clear this cache directory for any reason, you may do so by running the following shell command:
+
+```shell
+# replace APP with the name of your application
+sudo rm -rf /home/dokku/APP/cache/*
+```
+
+## Curl Build Timeouts
+
+Certain buildpacks may time out in retrieving dependencies via curl. This can happen when your network connection is poor or if there is significant network congestion. You may see a message similar to `gzip: stdin: unexpected end of file` after a curl command.
+
+If you see output similar this when deploying , you may need to override the curl timeouts to increase the length of time allotted to those tasks. You can do so via the `config` plugin:
+
+```shell
+dokku config:set --global CURL_TIMEOUT=600
+dokku config:set --global CURL_CONNECT_TIMEOUT=30
+```