suppress repeated hits

src/client/js/components/InstallerForm.jsx

@@ -13,9 +13,12 @@ class InstallerForm extends React.Component {
 
     this.state = {
       isValidUserName: true,
+      isSubmitButtonDisabled: false,
       selectedLang: {},
     };
     // this.checkUserName = this.checkUserName.bind(this);
+
+    this.clickHandler = this.clickHandler.bind(this);
   }
 
   componentWillMount() {
@@ -39,6 +42,13 @@ class InstallerForm extends React.Component {
     this.setState({ selectedLang: meta });
   }
 
+  clickHandler() {
+    this.setState({ isSubmitButtonDisabled: true });
+    setTimeout(() => {
+      this.setState({ isSubmitButtonDisabled: false });
+    }, 3000);
+  }
+
   render() {
     const hasErrorClass = this.state.isValidUserName ? '' : ' has-error';
     const unavailableUserId = this.state.isValidUserName
@@ -149,7 +159,7 @@ class InstallerForm extends React.Component {
             <input type="hidden" name="_csrf" value={this.props.csrf} />
 
             <div className="input-group mt-4 mb-3 d-flex justify-content-center">
-              <button type="submit" className="btn-fill btn btn-register" id="register">
+              <button type="submit" className="btn-fill btn btn-register" id="register" disabled={this.state.isSubmitButtonDisabled} onClick={this.clickHandler}>
                 <div className="eff"></div>
                 <span className="btn-label"><i className="icon-user-follow" /></span>
                 <span className="btn-label-text">{ this.props.t('Create') }</span>