random other warnings fixed

app/controllers/api/tokens_controller.rb

@@ -1,6 +1,6 @@
 class Api::TokensController < API::RestfulController
   def my_tokens
-    raise Pundit::NotAuthorizedError.new unless current_user
+    raise Pundit::NotAuthorizedError unless current_user
     instantiate_collection page_collection: false, timeframe_collection: false
     respond_with_collection
   end

app/controllers/topics_controller.rb

@@ -9,10 +9,10 @@ class TopicsController < ApplicationController
   # GET /topics/autocomplete_topic
   def autocomplete_topic
     term = params[:term]
-    if term && !term.empty?
-      @topics = policy_scope(Topic.where('LOWER("name") like ?', term.downcase + '%')).order('"name"')
+    @topics = if term && !term.empty?
+                policy_scope(Topic.where('LOWER("name") like ?', term.downcase + '%')).order('"name"')
               else
-      @topics = []
+                []
               end
     render json: autocomplete_array_json(@topics)
   end

app/models/user.rb

@@ -40,7 +40,7 @@ class User < ActiveRecord::Base
                             default_url: 'https://s3.amazonaws.com/metamaps-assets/site/user.png'
 
   # Validate the attached image is image/jpg, image/png, etc
-  validates_attachment_content_type :image, content_type: /\Aimage\/.*\Z/
+  validates_attachment_content_type :image, content_type: %r(\Aimage/.*\Z)
 
   # override default as_json
   def as_json(_options = {})