How can I get a reference to a method?

How can I get a reference to a method?

ruby methods hash reference

ruby

How to backreference in Ruby regular expression (regex) with gsub when I use grouping?

ruby regex reference gsub backreference

ruby

Ruby: Self reference in hash

ruby hash reference

ruby

Rails: violates foreign key constraint

ruby-on-rails ruby reference foreign-keys relational-database

ruby