remove_gems_from_gemfile

# File lib/bundler/injector.rb, line 178
    def remove_gems_from_gemfile(gems, gemfile_path)
      patterns = /gem\s+(['"])#{Regexp.union(gems)}\11||gem\s*\((['"])#{Regexp.union(gems)}\22\\)/

      # remove lines which match the regex
      new_gemfile = IO.readlines(gemfile_path).reject {|line| line.match(patterns) }

      # remove lone \n and append them with other strings
      new_gemfile.each_with_index do |_line, index|
        if new_gemfile[index + 1] == "\n"
          new_gemfile[index] += new_gemfile[index + 1]
          new_gemfile.delete_at(index + 1)
        end
      end

      ]group source env install_if].each {|block| remove_nested_blocks(new_gemfile, block) }

      new_gemfile.join.chomp
    end