Add RuboCop
Remove trailing blank lines
Use %w for array of words
Add surrounding space in default value assignment
Add space after comma
Add surrounding space for operators
Add space before block braces
Remove space inside brackets
Remove semicolons at the end of line
Align the elements of an array literal
Rename is_admin? to admin?
Exclude 'bin/**/*' from RuboCop
Remove unnecessary method arguments
Prefer Object#is_a? over Object#kind_of?
Use fail instead of raise to signal exceptions
Prefer single-quoted strings when string interpolation isn't needed
Avoid Perl-style global variables
Remove redundant self
Use def with parentheses when there are parameters
Remove parentheses for method calls with no arguments