chore: Remove 'DEPLOYMENT' env option

Add 'Installation' section

app/components/Sidebar/components/Version.js

@@ -0,0 +1,53 @@
+// @flow
+import * as React from 'react';
+import styled from 'styled-components';
+import Badge from 'components/Badge';
+import SidebarLink from './SidebarLink';
+import { version } from '../../../../package.json';
+
+export default function Version() {
+  // $FlowFixMe
+  const [releasesBehind, setReleasesBehind] = React.useState(0);
+
+  // $FlowFixMe
+  React.useEffect(() => {
+    async function loadReleases() {
+      let out = 0;
+      const res = await fetch(
+        'https://api.github.com/repos/outline/outline/releases'
+      );
+      const releases = await res.json();
+      for (const release of releases) {
+        if (release.tag_name === `v${version}`) {
+          return setReleasesBehind(out);
+        } else {
+          out++;
+        }
+      }
+    }
+    loadReleases();
+  }, []);
+
+  return (
+    <SidebarLink
+      href="https://github.com/outline/outline/releases"
+      label={
+        <React.Fragment>
+          v{version}
+          <br />
+          <LilBadge>
+            {releasesBehind === 0
+              ? 'Up to date'
+              : `${releasesBehind} version${
+                  releasesBehind === 1 ? '' : 's'
+                } behind`}
+          </LilBadge>
+        </React.Fragment>
+      }
+    />
+  );
+}
+
+const LilBadge = styled(Badge)`
+  margin-left: 0;
+`;