Add some UI for user-defined domain blocks (#6628)

* Keep list of blocked domains

Might be overkill, but I'm trying to follow the same logic as for blocked users

* Add basic domain block UI

* Add the domain blocks UI to Getting Started

* Fix undefined URL in `fetchDomainBlocks`

* Update all known users' domain_blocking relationship instead of just one's

app/javascript/mastodon/features/domain_blocks/index.js

@@ -0,0 +1,66 @@
+import React from 'react';
+import { connect } from 'react-redux';
+import ImmutablePropTypes from 'react-immutable-proptypes';
+import PropTypes from 'prop-types';
+import LoadingIndicator from '../../components/loading_indicator';
+import Column from '../ui/components/column';
+import ColumnBackButtonSlim from '../../components/column_back_button_slim';
+import DomainContainer from '../../containers/domain_container';
+import { fetchDomainBlocks, expandDomainBlocks } from '../../actions/domain_blocks';
+import { defineMessages, injectIntl } from 'react-intl';
+import ImmutablePureComponent from 'react-immutable-pure-component';
+import { debounce } from 'lodash';
+import ScrollableList from '../../components/scrollable_list';
+
+const messages = defineMessages({
+  heading: { id: 'column.domain_blocks', defaultMessage: 'Hidden domains' },
+  unblockDomain: { id: 'account.unblock_domain', defaultMessage: 'Unhide {domain}' },
+});
+
+const mapStateToProps = state => ({
+  domains: state.getIn(['domain_lists', 'blocks', 'items']),
+});
+
+@connect(mapStateToProps)
+@injectIntl
+export default class Blocks extends ImmutablePureComponent {
+
+  static propTypes = {
+    params: PropTypes.object.isRequired,
+    dispatch: PropTypes.func.isRequired,
+    domains: ImmutablePropTypes.list,
+    intl: PropTypes.object.isRequired,
+  };
+
+  componentWillMount () {
+    this.props.dispatch(fetchDomainBlocks());
+  }
+
+  handleLoadMore = debounce(() => {
+    this.props.dispatch(expandDomainBlocks());
+  }, 300, { leading: true });
+
+  render () {
+    const { intl, domains } = this.props;
+
+    if (!domains) {
+      return (
+        <Column>
+          <LoadingIndicator />
+        </Column>
+      );
+    }
+
+    return (
+      <Column icon='ban' heading={intl.formatMessage(messages.heading)}>
+        <ColumnBackButtonSlim />
+        <ScrollableList scrollKey='domain_blocks' onLoadMore={this.handleLoadMore}>
+          {domains.map(domain =>
+            <DomainContainer key={domain} domain={domain} />
+          )}
+        </ScrollableList>
+      </Column>
+    );
+  }
+
+}