Added README.md

README.md

+# release-server-middleware
+
+An Express middleware for release server.
+
+## Description
+
+Release server only works with [Semantic Versioning (SemVer)](https://semver.org/).
+
+Releases may be marked as private.
+
+The latest release is a release with the greatest version among non-private releases.
+
+## Usage
+
+```js
+app.use(releaseServerMiddleware(options))
+```
+
+### Options
+
+- `filesDir` `[string]` Default: `/files`
+    
+    Path to directory used to store releases.
+
+- `tmpFilesDir` `[string]` Default: `<filesDir>/.tmp`
+    
+    Path to directory used to store temp files.
+
+### API
+
+- Download the latest release
+    ```
+    GET /latest
+    ```
+- Get the latest release's info
+    ```
+    GET /latest/info
+    ```
+- Download specific release
+    ```
+    GET /:version
+    ```
+- Get specific release's info
+    ```
+    GET /:version/info
+    ```
+- Get all releases' info
+    ```
+    GET /releases
+    ```
+- Upload a release
+    ```
+    PUT /:version
+    Content-Type: multipart/form-data
+    [X-File-Name: file.ext]
+    [X-Private]
+    
+    file=...
+    ```
+    
+    `X-File-Name` - an optional header to set new file name.
+    
+    `X-Private` - an optional header to mark release as private.
+- Delete a release
+    ```
+    DELETE /:version
+    ```