Update .gitignore
Replace text files to markdown files
Copy contents to md file
Modify md syntax
modify headers syntax
Rough script
Revise session1
Revise section 2
section3
Emphasis misunderstanding point
Rivese verified_double part
Revise Building a mocking library
Revise Is my gem ready for Rails 4?
Revise Open source contributions around the world
Merge pull request #2 from saboyutaka/383

#383 English dictation was done.