diff --git a/db/migrate/20140516162515_add_unique_indexes_to_users.rb b/db/migrate/20140516162515_add_unique_indexes_to_users.rb
new file mode 100644
index 0000000..fb223e9
--- /dev/null
+++ b/db/migrate/20140516162515_add_unique_indexes_to_users.rb
@@ -0,0 +1,11 @@
+class AddUniqueIndexesToUsers < ActiveRecord::Migration
+  def change
+    remove_index "users", ["email"]
+    add_index "users", ["email"], unique: true
+    remove_index "users", ["login"]
+    add_index "users", ["login"], unique: true
+    remove_index "users", ["authentication_token"]
+    add_index "users", ["authentication_token"], unique: true
+  end
+end
+
diff --git a/db/schema.rb b/db/schema.rb
index a5de4ea..8613a47 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -11,13 +11,13 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20140515161337) do
+ActiveRecord::Schema.define(version: 20140516162515) do
 
   create_table "active_admin_comments", force: true do |t|
     t.string   "namespace"
     t.text     "body"
-    t.string   "resource_id",   null: false
-    t.string   "resource_type", null: false
+    t.string   "resource_id",   limit: 50, null: false
+    t.string   "resource_type", limit: 50, null: false
     t.integer  "author_id"
     t.string   "author_type"
     t.datetime "created_at"
@@ -408,9 +408,9 @@ ActiveRecord::Schema.define(version: 20140515161337) do
   end
 
   add_index "users", ["api_key"], name: "index_users_on_api_key", using: :btree
-  add_index "users", ["authentication_token"], name: "index_users_on_authentication_token", using: :btree
-  add_index "users", ["email"], name: "index_users_on_email", using: :btree
-  add_index "users", ["login"], name: "index_users_on_login", using: :btree
+  add_index "users", ["authentication_token"], name: "index_users_on_authentication_token", unique: true, using: :btree
+  add_index "users", ["email"], name: "index_users_on_email", unique: true, using: :btree
+  add_index "users", ["login"], name: "index_users_on_login", unique: true, using: :btree
   add_index "users", ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true, using: :btree
 
   create_table "watchings", force: true do |t|