Merge branch 'release/first_release'

* release/first_release: (35 commits)
  Add descriptions for each site
  Add a link to demo video
  Write good README
  Use factory
  Fix description
  Append newline at the end
  Fix AOJ xpath
  Add browse command
  Implement AtCoder submit method
  Add login feature
  Add AtCoder without login feature
  Fix AOJ download xpaths
  Add 'download' subcommand
  Initialize git repository
  Ignore exit status of `make build`
  Implement `all` command
  Fix AOJ
  User can see diff of wrong outputs
  Add description_xpath to AOJ
  Add a command to add test cases
  ...
Specify homepage
Merge branch 'hotfix/specify_homepage'

* hotfix/specify_homepage:
  Specify homepage
Merge branch 'hotfix/specify_homepage' into develop

* hotfix/specify_homepage:
  Specify homepage
Bump the version
Merge branch 'hotfix/version_0.0.2' into develop

* hotfix/version_0.0.2:
  Bump the version