Could not find i18n-0.6.9 in any of the sources - ruby

Question

Actually i'm getting that error inside the travis build.
My Gemfile is:
source 'http://rubygems.org'
# Gemfile for youtube_dlhelper
# Add dependencies required to use your gem here.
group :default do
gem 'highline'
gem 'dir'
gem 'fileutils2'
gem 'parseconfig'
gem 'viddl-rb'
gem 'streamio-ffmpeg'
gem 'rainbow'
gem 'gli'
end
# Add dependencies to develop your gem here.
# Include everything needed to run rake, tests, features, etc.
group :development do
gem 'rdoc', '~> 4.1.0'
gem 'bundler', '~> 1.0'
gem 'jeweler', '~> 2.0.0'
gem 'yard'
gem 'gem-release'
end
group :test do
gem 'shoulda', '>= 0'
gem 'rspec'
gem 'coveralls', require: false
gem 'simplecov'
end
The Gemfile.lock:
GEM
remote: http://rubygems.org/
specs:
activesupport (4.0.2)
i18n (~> 0.6, >= 0.6.4)
minitest (~> 4.2)
multi_json (~> 1.3)
thread_safe (~> 0.1)
tzinfo (~> 0.3.37)
addressable (2.3.5)
atomic (1.1.14)
builder (3.2.2)
coveralls (0.7.0)
multi_json (~> 1.3)
rest-client
simplecov (>= 0.7)
term-ansicolor
thor
descendants_tracker (0.0.3)
diff-lcs (1.2.5)
dir (0.1.2)
docile (1.1.1)
domain_name (0.5.15)
unf (>= 0.0.5, < 1.0.0)
faraday (0.8.8)
multipart-post (~> 1.2.0)
fileutils2 (0.2.0)
gem-release (0.7.1)
git (1.2.6)
github_api (0.11.1)
addressable (~> 2.3)
descendants_tracker (~> 0.0.1)
faraday (~> 0.8, < 0.10)
hashie (>= 1.2)
multi_json (>= 1.7.5, < 2.0)
nokogiri (~> 1.6.0)
oauth2
gli (2.8.1)
hashie (2.0.5)
highline (1.6.20)
http-cookie (1.0.2)
domain_name (~> 0.5)
httpauth (0.2.0)
i18n (0.6.9)
jeweler (2.0.0)
builder
bundler (>= 1.0)
git (>= 1.2.5)
github_api
highline (>= 1.6.15)
nokogiri (>= 1.5.10)
rake
rdoc
json (1.8.1)
jwt (0.1.8)
multi_json (>= 1.5)
mechanize (2.7.3)
domain_name (~> 0.5, >= 0.5.1)
http-cookie (~> 1.0)
mime-types (~> 2.0)
net-http-digest_auth (~> 1.1, >= 1.1.1)
net-http-persistent (~> 2.5, >= 2.5.2)
nokogiri (~> 1.4)
ntlm-http (~> 0.1, >= 0.1.1)
webrobots (>= 0.0.9, < 0.2)
mime-types (2.0)
mini_portile (0.5.2)
minitest (4.7.5)
multi_json (1.8.2)
multi_xml (0.5.5)
multipart-post (1.2.0)
net-http-digest_auth (1.4)
net-http-persistent (2.9)
nokogiri (1.6.1)
mini_portile (~> 0.5.0)
ntlm-http (0.1.1)
oauth2 (0.9.2)
faraday (~> 0.8)
httpauth (~> 0.2)
jwt (~> 0.1.4)
multi_json (~> 1.0)
multi_xml (~> 0.5)
rack (~> 1.2)
parseconfig (1.0.4)
progressbar (0.21.0)
rack (1.5.2)
rainbow (1.99.1)
rake (10.1.1)
rdoc (4.1.0)
json (~> 1.4)
rest-client (1.6.7)
mime-types (>= 1.16)
rspec (2.14.1)
rspec-core (~> 2.14.0)
rspec-expectations (~> 2.14.0)
rspec-mocks (~> 2.14.0)
rspec-core (2.14.7)
rspec-expectations (2.14.4)
diff-lcs (>= 1.1.3, < 2.0)
rspec-mocks (2.14.4)
shoulda (3.5.0)
shoulda-context (~> 1.0, >= 1.0.1)
shoulda-matchers (>= 1.4.1, < 3.0)
shoulda-context (1.1.6)
shoulda-matchers (2.4.0)
activesupport (>= 3.0.0)
simplecov (0.8.2)
docile (~> 1.1.0)
multi_json
simplecov-html (~> 0.8.0)
simplecov-html (0.8.0)
streamio-ffmpeg (1.0.0)
term-ansicolor (1.2.2)
tins (~> 0.8)
thor (0.18.1)
thread_safe (0.1.3)
atomic
tins (0.13.1)
tzinfo (0.3.38)
unf (0.1.3)
unf_ext
unf_ext (0.0.6)
viddl-rb (0.79)
mechanize
nokogiri
progressbar
webrobots (0.1.1)
yard (0.8.7.3)
PLATFORMS
ruby
DEPENDENCIES
bundler (~> 1.0)
coveralls
dir
fileutils2
gem-release
gli
highline
jeweler (~> 2.0.0)
parseconfig
rainbow
rdoc (~> 4.1.0)
rspec
shoulda
simplecov
streamio-ffmpeg
viddl-rb
yard
I searched inside Stackoverflow and found mostly the answer to make a bundle install or remove the lock and bundle install again.
Also i tried out to use bundle install -deployment but that one uses all dependencies, and my *.gem is ~60M big (by using rake release).
Is there a better solution?

Answer 1

I've found the solution. The problem was, that i have overwritten the install section of .travis.yml. So bundle install aren't executed and it doesn't found it.
So the fix:
from
install:
- sudo apt-get install ubuntu-restricted-extras ffmpeg
to
before_install:
- sudo apt-get install ubuntu-restricted-extras ffmpeg