PLT-3143 Added serverside code for custom Emoji (#3311)

* Added model objects for emoji

* Added database tables for emoji

* Added settings for custom emoji

* Added serverside APIs and unit tests for custom emoji

* Added additional validation to catch duplicate emoji names earlier on

* Added additional validation to prevent users from adding emoji as another user

webapp/components/admin_console/admin_sidebar.jsx

@@ -532,6 +532,16 @@ export default class AdminSidebar extends React.Component {
                                 }
                             >
                                 {customBranding}
+                                <AdminSidebarSection
+                                    name='custom_emoji'
+                                    title={
+                                        <FormattedMessage
+                                            id='admin.sidebar.customEmoji'
+                                            defaultMessage='Custom Emoji'
+                                        />
+
+                                    }
+                                />
                                 <AdminSidebarSection
                                     name='legal_and_support'
                                     title={

webapp/components/admin_console/custom_emoji_settings.jsx

@@ -0,0 +1,91 @@
+// Copyright (c) 2016 Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+import React from 'react';
+
+import * as Utils from 'utils/utils.jsx';
+
+import AdminSettings from './admin_settings.jsx';
+import BooleanSetting from './boolean_setting.jsx';
+import DropdownSetting from './dropdown_setting.jsx';
+import {FormattedMessage} from 'react-intl';
+import SettingsGroup from './settings_group.jsx';
+
+export default class CustomEmojiSettings extends AdminSettings {
+    constructor(props) {
+        super(props);
+
+        this.getConfigFromState = this.getConfigFromState.bind(this);
+
+        this.renderSettings = this.renderSettings.bind(this);
+
+        this.state = Object.assign(this.state, {
+            enableCustomEmoji: props.config.ServiceSettings.EnableCustomEmoji,
+            restrictCustomEmojiCreation: props.config.ServiceSettings.RestrictCustomEmojiCreation
+        });
+    }
+
+    getConfigFromState(config) {
+        config.ServiceSettings.EnableCustomEmoji = this.state.enableCustomEmoji;
+        config.ServiceSettings.RestrictCustomEmojiCreation = this.state.restrictCustomEmojiCreation;
+
+        return config;
+    }
+
+    renderTitle() {
+        return (
+            <h3>
+                <FormattedMessage
+                    id='admin.customization.customEmoji'
+                    defaultMessage='Custom Emoji'
+                />
+            </h3>
+        );
+    }
+
+    renderSettings() {
+        return (
+            <SettingsGroup>
+                <BooleanSetting
+                    id='enableCustomEmoji'
+                    label={
+                        <FormattedMessage
+                            id='admin.customization.enableCustomEmojiTitle'
+                            defaultMessage='Enable Custom Emoji:'
+                        />
+                    }
+                    helpText={
+                        <FormattedMessage
+                            id='admin.customization.enableCustomEmojiDesc'
+                            defaultMessage='Enable users to create custom emoji for use in chat messages.'
+                        />
+                    }
+                    value={this.state.enableCustomEmoji}
+                    onChange={this.handleChange}
+                />
+                <DropdownSetting
+                    id='restrictCustomEmojiCreation'
+                    values={[
+                        {value: 'all', text: Utils.localizeMessage('admin.customization.restrictCustomEmojiCreationAll', 'Allow everyone to create custom emoji')},
+                        {value: 'system_admin', text: Utils.localizeMessage('admin.customization.restrictCustomEmojiCreationSystemAdmin', 'Only allow system admins to create custom emoji')}
+                    ]}
+                    label={
+                        <FormattedMessage
+                            id='admin.customization.restrictCustomEmojiCreationTitle'
+                            defaultMessage='Restrict Custom Emoji Creation:'
+                        />
+                    }
+                    helpText={
+                        <FormattedMessage
+                            id='admin.customization.restrictCustomEmojiCreationDesc'
+                            defaultMessage='Restrict the creation of custom emoji to certain users.'
+                        />
+                    }
+                    value={this.state.restrictCustomEmojiCreation}
+                    onChange={this.handleChange}
+                    disabled={!this.state.enableCustomEmoji}
+                />
+            </SettingsGroup>
+        );
+    }
+}