Unable to add larger GPG key on MySQL

Summary

Can not add larger GPG key when using MySQL (500 error)

Steps to reproduce

Add larger GPG key via https://gitar.io/profile/gpg_keys - for example a GPG key that contains multiple email addresses and a profile image.

Relevant logs and/or screenshots

ActiveRecord::StatementInvalid (Mysql2::Error: Data too long for column 'key' at row 1: INSERT INTO `gpg_keys` (`primary_keyid`, `fingerprint`, `key`, `user_id`, `created_at`, 

Results of GitLab environment info

Expand for output related to GitLab environment info

System information
System:		Debian 9.4
Current User:	git
Using RVM:	no
Ruby Version:	2.3.7p456
Gem Version:	2.5.2.3
Bundler Version:1.16.2
Rake Version:	12.3.0
Redis Version:	3.2.6
Git Version:	2.17.0
Sidekiq Version:5.0.5
Go Version:	go1.8.7 linux/amd64
GitLab information
Version:	10.7.3
Revision:	2555d6c1a2
Directory:	/home/git/gitlab
DB Adapter:	mysql2
URL:		https://gitar.io
HTTP Clone URL:	https://gitar.io/some-group/some-project.git
SSH Clone URL:	git@gitar.io:some-group/some-project.git
Using LDAP:	no
Using Omniauth:	no
GitLab Shell
Version:	7.1.2
Repository storage paths:

• default: /home/git/repositories Hooks: /home/git/gitlab-shell/hooks Git: /usr/local/bin/git

Possible fixes

A fix similar to this MR: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/11024. I do understand that the GitLab team does not want to support MySQL, but I truly feel that if migrations are properly implemented this is a non-issue. E.g. by using LONGTEXT instead of TEXT.