Add file path source option (`--file`) to plugin installation

Convenience option for installing plugins from a local repository, using the local path:

    bundle plugin install --file /path/to/bundler-dependency_graph bundler-dependency_graph

1 files changed, 11 insertions, 0 deletions

diff --git a/spec/plugins/install_spec.rb b/spec/plugins/install_spec.rb
index 9304d78062..7c0212ed76 100644
--- a/spec/plugins/install_spec.rb
+++ b/spec/plugins/install_spec.rb
@@ -122,6 +122,17 @@ RSpec.describe "bundler plugin install" do
       expect(out).to include("Installed plugin foo")
       plugin_should_be_installed("foo")
     end
+
+    it "installs form a local git source" do
+      build_git "foo" do |s|
+        s.write "plugins.rb"
+      end
+
+      bundle "plugin install foo --file #{lib_path("foo-1.0")}"
+
+      expect(out).to include("Installed plugin foo")
+      plugin_should_be_installed("foo")
+    end
   end
 
   context "Gemfile eval" do