add project level rubocop config file
Prefer single-quoted strings when you don't need string interpolation or special symbols.
space before and after { and before }
Trailing whitespace detected.
Space inside square brackets detected.
Extra blank line detected.
Use the new Ruby 1.9 hash syntax.
Space between { and | missing.
Favor modifier if/unless usage when you have a single-line body. Another good alternative is the usage of control flow &&/||.
Prefer single-quoted strings when you don't need string interpolation or special symbols.