https://developer.atlassian.com/jiradev/jira-platform/building-jira-add-ons/jira-plugins2-overview/jira-plugin-module-types/custom-field-plugin-module/how-to-add-searching-to-a-custom-field

https://developer.atlassian.com/jiradev/jira-platform/building-jira-add-ons/jira-plugins2-overview/jira-plugin-module-types/custom-field-plugin-module

https://developer.atlassian.com/jiradev/jira-platform/guides/fields/tutorial-custom-fields-in-jira

https://answers.atlassian.com/questions/16394860/how-to-specify-valid-searcher-for-custom-field-types

https://answers.atlassian.com/questions/69644/basic-text-searcher-not-showing-up

http://www.j-tricks.com/tutorials/custom-field-searchers

Source Code