Initial attempt at setting up a Follower scheme

server/sequelize/associations/User.js

@@ -6,6 +6,7 @@ module.exports = models => {
     Status,
     Review,
     Recommendation,
+    Follow,
   } = models;
 
   User.belongsTo(PermissionLevel, {
@@ -18,6 +19,14 @@ module.exports = models => {
   User.hasMany(Recommendation, {
     foreignKey: 'toUser',
   });
+  User.hasMany(Follow, {
+    foreignKey: 'follower',
+    as: 'Followers',
+  });
+  User.belongsTo(Follow.scope('internal'), {
+    foreignKey: 'following',
+    as: 'Follows',
+  });
 
   return User;
 }

server/sequelize/models/Follow.js

@@ -0,0 +1,70 @@
+const Sequelize = require('sequelize');
+
+module.exports = sequelize => sequelize.define('Follow', {
+  id: {
+    type: Sequelize.INTEGER,
+    primaryKey: true,
+    autoIncrement: true,
+  },
+  follower: {
+    type: Sequelize.INTEGER,
+    allowNull: false,
+    references: {
+      model: sequelize.models.User,
+      key: 'id',
+      deferrable: Sequelize.Deferrable.INITIALLY_IMMEDIATE,
+    },
+  },
+  followerDomain: {
+    type: Sequelize.TEXT,
+    allowNull: true,
+    comment: 'A null value means that the following id is on this server, otherwise it is external.',
+  },
+  following: {
+    type: Sequelize.INTEGER,
+    allowNull: false,
+    references: {
+      model: sequelize.models.User,
+      key: 'id',
+      deferrable: Sequelize.Deferrable.INITIALLY_IMMEDIATE,
+    },
+  },
+  followingDomain: {
+    type: Sequelize.TEXT,
+    allowNull: true,
+    comment: 'A null value means that the following id is on this server, otherwise it is external.',
+  },
+
+  // Timestamps
+  createdAt: {
+    type: Sequelize.DATE,
+    allowNull: false,
+    defaultValue: Sequelize.NOW,
+  },
+  updatedAt: {
+    type: Sequelize.DATE,
+    allowNull: false,
+    defaultValue: Sequelize.NOW,
+  },
+}, {
+  indexes: [
+    {
+      fields: ['follower'],
+    },
+    {
+      fields: ['following', 'domain'],
+    },
+  ],
+  scopes: {
+    internal: {
+      where: {
+        followerDomain: {
+          [Sequelize.Op.is]: null,
+        },
+        followingDomain: {
+          [Sequelize.Op.is]: null,
+        },
+      },
+    },
+  }
+});