Generate key for each input so we can upload the same file even after deleting

app/assets/javascripts/components/features/compose/components/upload_button.jsx

@@ -11,7 +11,8 @@ const UploadButton = React.createClass({
   propTypes: {
     disabled: React.PropTypes.bool,
     onSelectFile: React.PropTypes.func.isRequired,
-    style: React.PropTypes.object
+    style: React.PropTypes.object,
+    key: React.PropTypes.number
   },
 
   mixins: [PureRenderMixin],
@@ -36,7 +37,7 @@ const UploadButton = React.createClass({
     return (
       <div style={this.props.style}>
         <IconButton icon='photo' title={intl.formatMessage(messages.upload)} disabled={this.props.disabled} onClick={this.handleClick} size={24} />
-        <input ref={this.setRef} type='file' multiple={false} onChange={this.handleChange} disabled={this.props.disabled} style={{ display: 'none' }} />
+        <input key={this.props.key} ref={this.setRef} type='file' multiple={false} onChange={this.handleChange} disabled={this.props.disabled} style={{ display: 'none' }} />
       </div>
     );
   }

app/assets/javascripts/components/features/compose/containers/upload_button_container.jsx

@@ -4,6 +4,7 @@ import { uploadCompose } from '../../../actions/compose';
 
 const mapStateToProps = state => ({
   disabled: state.getIn(['compose', 'is_uploading']) || (state.getIn(['compose', 'media_attachments']).size > 3 || state.getIn(['compose', 'media_attachments']).some(m => m.get('type') === 'video')),
+  key: Math.floor((Math.random() * 0x10000))
 });
 
 const mapDispatchToProps = dispatch => ({