In Rails 3's "bundle install" of local gem (frozen gem), keep getting "Source does not contain any versions of ..."?

I am using a gem whic开发者_如何学Pythonh is in vendor/gems/some-api-0.1.0, copied over from another project, and added to Gemfile:

gem 'some-api', :path => '~/development/myproj/vendor/gems/some-api-0.1.0'

but if I do the following, it will fail with the message:

$ bundle install
Fetching source index for http://rubygems.org/
Could not find gem 'some-api (>= 0)' in source at ~/development/myproj/vendor/gems/some-api-0.1.0.
Source does not contain any versions of 'some-api (>= 0)'

Searching on the net seem to suggest needing a gemspec? So I need to write up a .gemspec some where, is that true? Can someone shred light of how it is done in this situation?

There are many other similar posts on stackoverflow, but just in case someone stumble across this post:

For some reason, when you are trying to use a gem from local source, you need to specify exactly which version of the gem you are using, e.g.

gem 'some-api', '0.2.0', :path => '~/development/myproj/vendor/gems/some-api-0.1.0'

Just claiming there is a gem in the :path doesn't mean there actually is a gem there. Gems have gemspec files describing the name of the gem, what files belong to the gem, and various other information.

If some-api-0.1.0 should contain a file named some-api.gemspec in the :path directory, and it should contain information about the gem that bundler could use to require the gem out of the :path.