Adds Steam auth and API

models/User.js

@@ -2,13 +2,15 @@ var mongoose = require('mongoose');
 var bcrypt = require('bcrypt-nodejs');
 
 var userSchema = new mongoose.Schema({
-  email: { type: String, unique: true },
+  email: { type: String, unique: true, sparse: true },
   password: String,
 
   facebook: { type: String, unique: true, sparse: true },
   twitter: { type: String, unique: true, sparse: true },
   google: { type: String, unique: true, sparse: true },
   github: { type: String, unique: true, sparse: true },
+  steam: { type: String, unique: true, sparse: true },
+
   tokens: Array,
 
   profile: {