Add more Vim version in unit test

.travis.yml

@@ -1,3 +1,5 @@
+# This config is based on lightline.vim <https://github.com/itchyny/lightline.vim/blob/master/.travis.yml>
+
 language: ruby
 rvm:
     - 2.0.0
@@ -6,5 +8,24 @@ install:
 before_script:
     - bundle install
     - bundle show
+    - (if ! test -d $HOME/vim-$VIM_VERSION/bin; then
+         git clone https://github.com/vim/vim $HOME/vim &&
+         cd $HOME/vim &&
+         git checkout v$VIM_VERSION &&
+         ./configure --prefix=$HOME/vim-$VIM_VERSION &&
+         make &&
+         make install;
+       fi)
+
+cache:
+    directories:
+      - $HOME/vim-$VIM_VERSION
+
+env:
+    - VIM_VERSION=8.0.0000
+    - VIM_VERSION=7.4
+
 script:
+    - export PATH=$HOME/vim-$VIM_VERSION/bin:$PATH
+    - cd $TRAVIS_BUILD_DIR
     - rake ci

Gemfile

@@ -1,4 +1,4 @@
 source 'https://rubygems.org'
 
-gem 'vim-flavor', '~> 1.1'
+gem 'vim-flavor', '~> 2.2.2'
 gem 'rake'