require authentication for todos,

use in-memody db for tests

package.json

@@ -18,6 +18,7 @@
     "express-jwt": "^5.3.1",
     "jsonwebtoken": "^8.2.1",
     "mongoose": "^5.1.1",
+    "mongoose-unique-validator": "^2.0.1",
     "morgan": "^1.9.0",
     "passport": "^0.4.0",
     "passport-local": "^1.0.0",
@@ -30,6 +31,7 @@
     "eslint-plugin-import": "^2.12.0",
     "eslint-plugin-jest": "^21.15.2",
     "jest": "^22.4.4",
+    "mongodb-memory-server": "^1.7.4",
     "nodemon": "^1.17.5",
     "supertest": "^3.1.0"
   },