Fixed find_category #1

app/controllers/categories_controller.rb

@@ -15,6 +15,8 @@ class CategoriesController < ApplicationController
   def find_category
     if params[:id].to_i > (Category.count + 1)
       redirect_to error_path
+    elsif is_number?(params[:id]) == false
+      redirect_to error_path
     else
       @category = Category.find(params[:id])
     end