My gem file contains:

gem "breadcrumb", :git => "git@github.com:mjacobus/Breadcrumb.git"

gem "simple_menu", :git => "git@github.com:mjacobus/simple_menu.git"

The first gem installs as expected, but the second one fails.

Updating git@github.com:mjacobus/simple_menu.git
Fetching gem metadata from https://rubygems.org/........
Could not find gem 'simple_menu (>= 0) ruby' in git@github.com:mjacobus/simple_menu.git (at master).
Source does not contain any versions of 'simple_menu (>= 0) ruby'

Similar posts points to the lack of the .gemspec file, but this file exists. https://github.com/mjacobus/simple_menu/blob/master/simple_menu.gemspec

I am probably doing something stupid that someone else's eyes will be able to see.

edit

I cloned the repo into the vendor/plugins folder and changed my Gemfile

gem "simple_menu", :path => "vendor/plugins/simple_menu"

Bundle install issues now the error:

bundle install
Fetching gem metadata from https://rubygems.org/.......
Could not find gem 'simple_menu (>= 0) ruby' in source at vendor/plugins/simple_menu.
Source does not contain any versions of 'simple_menu (>= 0) ruby'

edit 2

I knew it was a stupid error. The gem name was not correct.

https://github.com/mjacobus/simple_menu/commit/1afca04b08a084dafb9bdf6e595a2bb9a7b7a55f