add invitation.jsx widget

src/widgets/invitation.jsx

@@ -0,0 +1,43 @@
+// A single topic or user.
+import React from 'react';
+import { FormattedMessage } from 'react-intl';
+
+export default class Invitation extends React.PureComponent {
+  constructor(props) {
+    super(props);
+
+    this.handleButtonAction = this.handleButtonAction.bind(this);
+  }
+
+  handleButtonAction(evt, data) {
+    evt.preventDefault();
+    console.log("button clicked", data);
+    this.props.onAction(data);
+  }
+
+  render() {
+    return (
+      <div className="accept-invite-panel">
+        <div className="title">
+          <FormattedMessage id="chat_invitation"
+            defaultMessage="You are invited to start a new chat. What would you like to do?"
+            description="New chat invitation message: [Accept] [Ignore] [Block]." />
+        </div>
+        <div className="footer">
+          <button className="blue" onClick={event => { this.handleButtonAction(event, "accept"); }}>
+            <FormattedMessage id="chat_invitation_accept"
+              defaultMessage="Accept" description="Action [Accept] for chat invitation." />
+          </button>
+          <button className="white" onClick={event => { this.handleButtonAction(event, "delete"); }}>
+            <FormattedMessage id="chat_invitation_ignore"
+              defaultMessage="Ignore" description="Action [Ignore] for chat invitation." />
+          </button>
+          <button className="white" onClick={event => { this.handleButtonAction(event, "block"); }}>
+            <FormattedMessage id="chat_invitation_block"
+              defaultMessage="Block" description="Action [Block] for chat invitation." />
+          </button>
+        </div>
+      </div>
+    );
+  }
+};