path_finder.rb

class PathFinder

  def initialize(maze, start_pos=nil, end_pos=nil)
    @maze        = maze  # NxN, [row][col]
    @visited_pos = {}    # pos => entry_pos
    @start_pos   = (start_pos || [0,0])
    @end_pos     = (end_pos   || [@maze.length - 1 , @maze[0].length - 1])
  end

  def find_path
    current_pos = nil
    entry_pos   = [nil,nil]
    pos_queue   = [ { :pos => @start_pos, :entry => entry_pos } ]

    while current_pos = pos_queue.shift

      @visited_pos[current_pos[:pos]] = current_pos[:entry]

      if current_pos[:pos] == @end_pos
        break
      end

      neighbors = find_neighbors(current_pos[:pos])
      neighbors.each do |neighbor|
        pos_queue << { :pos => neighbor, :entry => current_pos[:pos] }
      end
      entry_pos = current_pos[:pos]
    end

    rebuild_path(current_pos[:pos])

  end

  private

    def rebuild_path(pos)
      path = [pos]
      while pos != @start_pos
        pos = @visited_pos[pos]
        path.unshift pos
      end
      path
    end

    def find_neighbors(pos)
      neighbors = []
      row, col = pos
      query_positions = [
                      [row - 1, col],
                      [row + 1, col],
                      [row, col - 1],
                      [row, col + 1]
                    ]
      query_positions.each do |r, c|
        if (r < 0 ||  c < 0 || r == @maze.length || c == @maze[0].length)
          next
        end
        # add if neighbor is an open path, and has not been visited
        if @maze[r][c] == "1" && @visited_pos[[r,c]].nil?
          neighbors << [r,c]
        end
      end
      neighbors
    end

end

Use docker:
docker run vividfarmer/armory:mazerunner