Merge pull request #17 from suprbh/master

Add server-side files
Add package.json and comment out some code so that express server can start
Merge pull request #19 from ryojiosawa/feat/signup

Add package.json and comment out some code so that express server can start
Add .travis.yml
Merge pull request #20 from ryojiosawa/feat/signup

Add .travis.yml
Merge pull request #18 from suprbh/master

Add more server-side files: mongodb related
removing link.js