message_groups

• id int(10) unsigned NOT NULL AUTO_INCREMENT,
• action varchar(64) NOT NULL,
• type ENUM('client', 'staff', 'shared') DEFAULT 'client',
• plugin_dir varchar(64) NOT NULL
• PRIMARY KEY (`id`),
• INDEX `type` (`type`)

messages

• id int(10) unsigned NOT NULL AUTO_INCREMENT,
• message_group_id int(10) unsigned NOT NULL,
• company_id int(10) unsigned NOT NULL,
• text mediumtext COLLATE utf8_unicode_ci
• PRIMARY KEY (`id`),
• INDEX `message_group_id` (`message_group_id`)

message_content

• message_id int(10) unsigned NOT NULL,
• type ENUM('sms') DEFAULT 'sms',
• content mediumtext COLLATE utf8_unicode_ci
• PRIMARY KEY (`message_id`, `type`)

Add a Messages model

• add
• edit
• delete
• get
• getAll
• getByDir
• getTypes

Add a new setting page under Settings >> Company >> Messaging called Message Templates

• This page should contain a table of message templates including
  • Name
  • Types
  • Options (with Edit link)

Add a new Edit Message Template page

• Create a tab and textarea field for every messenger type
• Create a checkbox on each tab to enable/disable the messenger type

Add permissions for these settings pages