Move `ReduxStore` to the `@uppy/store-redux` package.

Steps taken:

```bash
cp -R package-template packages/@uppy/store-redux
git mv src/store/ReduxStore.js packages/@uppy/store-redux/src/index.js
git mv src/store/ReduxStore.test.js packages/@uppy/store-redux/src/index.test.js
vim packages/@uppy/store-redux/src/index.test.js # update require()
vim packages/@uppy/store-redux/{package.json,README.md} # Add cuid dependency, update
```

packages/@uppy/store-redux/LICENSE

@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2018 Transloadit
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

packages/@uppy/store-redux/README.md

@@ -0,0 +1,53 @@
+# @uppy/store-redux
+
+<img src="https://uppy.io/images/logos/uppy-dog-head-arrow.svg" width="120" alt="Uppy logo: a superman puppy in a pink suit" align="right">
+
+<a href="https://www.npmjs.com/package/@uppy/store-redux"><img src="https://img.shields.io/npm/v/@uppy/store-redux.svg?style=flat-square"></a>
+<a href="https://travis-ci.org/transloadit/uppy"><img src="https://img.shields.io/travis/transloadit/uppy/master.svg?style=flat-square" alt="Build Status"></a>
+
+The `ReduxStore` stores Uppy state on a key in an existing Redux store.
+The `ReduxStore` dispatches `uppy/STATE_UPDATE` actions to update state.
+When the state in Redux changes, it notifies Uppy.
+This way, you get most of the benefits of Redux, including support for the Redux Devtools and time traveling!
+
+Uppy is being developed by the folks at [Transloadit](https://transloadit.com), a versatile file encoding service.
+
+## Example
+
+```js
+const { combineReducers, createStore } = require('redux')
+const Uppy = require('@uppy/core')
+const ReduxStore = require('@uppy/store-redux')
+const reducers = require('./reducers')
+
+const reducer = combineReducers({
+  ...reducers,
+  uppy: ReduxStore.reducer
+})
+
+const store = createStore(reducer)
+
+const uppy = Uppy({
+  store: ReduxStore({
+    store: store
+  })
+})
+```
+
+## Installation
+
+```bash
+$ npm install @uppy/store-redux --save
+```
+
+We recommend installing from npm and then using a module bundler such as [Webpack](http://webpack.github.io/), [Browserify](http://browserify.org/) or [Rollup.js](http://rollupjs.org/).
+
+Alternatively, you can also use this plugin in a pre-built bundle from Transloadit's CDN: Edgly. In that case `Uppy` will attach itself to the global `window.Uppy` object. See the [main Uppy documentation](https://uppy.io/docs/#Installation) for instructions.
+
+## Documentation
+
+Documentation for this plugin can be found on the [Uppy website](https://uppy.io/docs/DOC_PAGE_HERE).
+
+## License
+
+[The MIT License](./LICENSE).

packages/@uppy/store-redux/package.json

@@ -0,0 +1,26 @@
+{
+  "name": "@uppy/store-redux",
+  "description": "Make Uppy use your existing Redux store.",
+  "version": "0.25.5",
+  "license": "MIT",
+  "main": "lib/index.js",
+  "jsnext:main": "src/index.js",
+  "types": "types/index.d.ts",
+  "keywords": [
+    "file uploader",
+    "plugin name and other keywords",
+    "uppy",
+    "uppy-plugin"
+  ],
+  "homepage": "https://uppy.io",
+  "bugs": {
+    "url": "https://github.com/transloadit/uppy/issues"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/transloadit/uppy.git"
+  },
+  "dependencies": {
+    "cuid": "^2.1.1"
+  }
+}

src/store/ReduxStore.test.js → packages/@uppy/store-redux/src/index.test.js

@@ -1,4 +1,4 @@
-const ReduxStore = require('./ReduxStore')
+const ReduxStore = require('./index')
 const Redux = require('redux')
 
 describe('ReduxStore', () => {