Could not find mysqltopostgres (>= 0) (Gem::LoadError) dependency.rb:256:into_spec'

[ElmiyaAgnes]

Hello,
Please, help me to resolve this issue.

home/mysql2postgres$ mysqltopostgres
/usr/lib/ruby/1.9.1/rubygems/dependency.rb:247:in to_specs': Could not find mysqltopostgres (>= 0) amongst [addressable-2.4.0, builder-3.2.2, bundler-1.11.2, bundler-unload-1.0.2, descendants_tracker-0.0.4, executable-hooks-1.3.2, faraday-0.9.2, gem-wrappers-1.2.7, git-1.2.9.1, github_api-0.13.1, hashie-3.4.3, highline-1.7.8, jeweler-2.0.1, json-1.8.3, jwt-1.5.2, mini_portile2-2.0.0, multi_json-1.11.2, multi_xml-0.5.5, multipart-post-2.0.0, mysql-pr-2.9.11, nokogiri-1.6.7.2, oauth2-1.0.0, pg-0.18.4, postgres-pr-0.7.0, postgres-pr-0.6.3, power_assert-0.2.7, rack-1.6.4, rake-10.5.0, rdoc-4.2.1, rubygems-bundler-1.4.4, rvm-1.11.3.9, test-unit-3.1.7, test-unit-2.5.5, thread_safe-0.3.5] (Gem::LoadError) from /usr/lib/ruby/1.9.1/rubygems/dependency.rb:256:into_spec'
from /usr/lib/ruby/1.9.1/rubygems.rb:1231:in gem' from /usr/local/bin/mysqltopostgres:22:in

'

I had done,
home/mysql2postgres$ sudo gem install mysqltopostgres-0.3.0.gem
Successfully installed mysqltopostgres-0.3.0
1 gem installed
Installing ri documentation for mysqltopostgres-0.3.0...
Installing RDoc documentation for mysqltopostgres-0.3.0...

and gem 'mysqltopostgres', git: "https://github.com/maxlapshin/mysql2postgres.git into my gemfile.