Created README and LICENCE (#17)

LICENCE

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+MIT License
+
+Copyright (c) 2022 Aleksandras Sukelovic
+
+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.

README.md

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-"# react-suspended-query"
+# react-suspended-query
+
+## Inspiration
+
+This package was inspired by [SWR](https://swr.vercel.app/).
+
+
+## Installation
+
+```bash
+npm i react-suspended-query
+```
+
+## What is this
+
+This is a react fetching library based on [React Suspense](https://reactjs.org/docs/react-api.html#reactsuspense).
+
+## The problem
+
+The classic way of fetching data in React looks like this:
+
+```jsx
+const SomeComponent = () => {
+    // Create state for data, error and loading
+    const [data, setData] = useState(null)
+    const [error, setError] = useState(null)
+    const [loading, setLoading] = useState(true)
+
+    // Create useEffect to fetch data
+    useEffect(() => {
+        fetch('https://some-url/data')
+            .then(setData)
+            .catch(setError)
+            .finally(() => setLoading(false))
+    }, [])
+
+    // Make conditional rendering
+    if (loading) {
+        return <Spinner />
+    }
+
+    if (error) {
+        return <ErrorMessage error={error} />
+    }
+
+    return <div>
+        {data}
+    </div>
+}
+```
+
+As you can see, there is a lot of boilerplate code and it is hard to write components like that.
+
+## The solution with Suspense
+
+In React 18 you can use Suspense for data fetching, but be aware that it is still experimental feature.
+
+New API look like this:
+
+```jsx
+const App = () => {
+
+    // Wrap your component with ErrorBoundary to handle error state and Suspense to handle loading state
+    // Now we can define the error state of our App in one place as well as loading state
+    return <CacheGroup.Provider>
+        <ErrorBoundary>
+            <Suspense fallback={<Spinner />}>
+                <SomeComponent />
+            </Suspense>
+        </ErrorBoundary>
+    <CacheGroup.Provider>
+}
+
+const SomeComponent = () => {
+    const data = useQuery('https://some-url/data', fetch)
+
+    return <div>
+        {data}
+    </div>
+}
+```
+
+See [ErrorBoundary](https://reactjs.org/docs/error-boundaries.html#gatsby-focus-wrapper) and [Suspense](https://reactjs.org/docs/react-api.html#reactsuspense) from React documentation.
+
+## Cache groups
+
+react-suspended-query provides the possibility to define cache groups. By default, you must wrap your component with `CacheGroup.Provider`, which will cache all fetches in children components. In general, some fetches depend on variables and others are consistent. To handle these cases, you can create multiple cache groups in one App.
+
+## API
+
+### useQuery
+
+#### Calls given fetcher and processes the query:
+- When promise is pending - renders Suspense.
+- When fetcher throws error - passes it up the component tree.
+- When promise resolves - returns data.
+
+#### Arguments:
+1. `key` - a string or an array of values fetcher depends on.
+2. `fetcher` - function, which accepts your `key` in arguments and returns promise.
+
+#### Example usage:
+```jsx
+const data = useQuery(['https://some-url/data', id], (key, id) => fetch(`${key}/${id}`))
+```
+
+<br/>
+
+### createCacheGroup
+
+#### Used to create cache group provider. Returns CacheGroup.
+
+#### Example usage:
+```jsx
+const CacheGroup = createCacheGroup()
+
+const App = () => {
+    return <CacheGroup.Provider>
+        {/* JSX */}
+    </CacheGroup.Provider>
+}
+```
+<br/>
+
+## License
+
+The MIT License.