Added Searching Features

* Added Thread Search Feature

* Added User Search Feature

* Re-organized searching, added @mention support to author search

db/migrate/20170522210610_add_search_indexes.rb

@@ -0,0 +1,8 @@
+class AddSearchIndexes < ActiveRecord::Migration
+  def change
+    add_index :forumthreads, [:title, :content], type: :fulltext
+    add_index :forumthreads, :title, type: :fulltext
+    add_index :forumthreads, :content, type: :fulltext    
+    add_index :threadreplies, :content, type: :fulltext
+  end
+end