update active record configuration after updation

lib/hijacker.rb

@@ -187,13 +187,14 @@ def self.root_config
   end
 
   def self.database_configurations
-    ActiveRecord::Base.configurations
+    ActiveRecord::Base.configurations = YAML.load(File.read('config/database.yml'))
   end
 
   # this should establish a connection to a database containing the bare minimum
   # for loading the app, usually a sessions table if using sql-based sessions.
   def self.establish_root_connection
-    ActiveRecord::Base.establish_connection('root')
+    @dbconfig = YAML.load(File.read('config/database.yml'))
+    ActiveRecord::Base.establish_connection @dbconfig['root']
   end
 
   def self.processing_sister_site?

lib/hijacker/base_model.rb

@@ -1,6 +1,6 @@
 module Hijacker
   class BaseModel < ActiveRecord::Base
-    establish_connection('root')
+    establish_connection(:root)
 
     self.abstract_class = true
   end

lib/hijacker/database.rb

@@ -59,7 +59,7 @@ def self.find_by_name(name)
   end
 
   def self.current
-    find(:first, :conditions => {:database => Hijacker.current_client})
+    find_by(database: Hijacker.current_client)
   end
 
   # returns a string or nil

lib/hijacker/host.rb

@@ -1,6 +1,6 @@
 class Hijacker::Host < Hijacker::BaseModel
 
-  validates_format_of :hostname, :with => /^(#{URI::REGEXP::PATTERN::HOST}|#{URI::REGEXP::PATTERN::IPV6ADDR})$/
+  validates_format_of :hostname, :with => /\A(#{URI::REGEXP::PATTERN::HOST}|#{URI::REGEXP::PATTERN::IPV6ADDR})\z/
   belongs_to :slave, class_name: "Hijacker::Host"
 
 end