Add Release Drafter app

_apps/release-drafter.md

@@ -0,0 +1,48 @@
+---
+title: Release Drafter
+description: Drafts your next release notes as pull requests are merged into master.
+slug: release-drafter
+screenshots:
+- https://raw.githubusercontent.com/toolmantim/release-drafter/master/design/screenshot.png
+authors: [ toolmantim ]
+repository: toolmantim/release-drafter
+host: https://release-drafter.now.sh
+---
+
+## Usage
+
+1. Install the [Release Drafter GitHub App](https://github.com/apps/release-drafter) into the repositories you wish to create releases in.
+2. Add a `.github/release-drafter.yml` configuration file to each repository.
+
+## Example
+
+For example, take the following `.github/release-drafter.yml` file in a repository:
+
+```yml
+template: |
+  ## What's Changed
+
+  $CHANGES
+```
+
+As pull requests are merged, a draft release is kept up-to-date listing the changes, ready to publish when you’re ready.
+
+## Template variables
+
+You can use any of the following variables in your template, and they’ll be substituted when the release is regenerated:
+
+|Variable|Description|
+|-|-|
+|`$CHANGES`|The markdown list of pull requests that have been merged.|
+|`$PREVIOUS_TAG`|The previous releases’s tag.|
+
+## Configuration options
+
+You can configure Release Drafter using the following key in your `.github/release-drafter.yml` file:
+
+|Key|Required|Description|
+|-|-|-|
+|`template`|Required|The template for the body of the draft release. Use [template variables](#template-variables) to insert values.|
+|`branches`|Optional|The branches to listen for configuration updates to `.github/release-drafter.yml` and for merge commits. Useful if you want to test the app on a pull request branch. Default is the repository’s default branch.|
+
+Release Drafter also supports [Probot Config](https://github.com/probot/probot-config), if you want to store your configuration files in a central repository.