Add OAuth2 authentication (#147)

- Added Site settings > Authentication section
- Create/edit/delete your custom oauth2 configurations
- Login or signup with oauth2

app/javascript/components/common/CopyToClipboardButton.tsx

@@ -0,0 +1,43 @@
+import * as React from 'react';
+import I18n from 'i18n-js';
+import { useState } from 'react';
+
+interface Props {
+  label: string;
+  textToCopy: string;
+  copiedLabel?: string;
+}
+
+const CopyToClipboardButton = ({
+  label,
+  textToCopy,
+  copiedLabel = I18n.t('common.copied')
+}: Props) => {
+  const [ready, setReady] = useState(true);
+
+  const alertError = () =>
+    alert(`Error in automatically copying to clipboard. Please copy the callback url manually:\n\n${textToCopy}`);
+
+  return (
+    ready ?
+      <a
+        onClick={() => {
+          if (navigator.clipboard) {
+            navigator.clipboard.writeText(textToCopy).then(() => {
+              setReady(false);
+              setTimeout(() => setReady(true), 2000);
+            },
+            alertError);
+          } else {
+            alertError();
+          }
+        }}
+      >
+        {label}
+      </a>
+    :
+      <span>{copiedLabel}</span>
+  );
+};
+
+export default CopyToClipboardButton;