Add docs

src/lx_chess.cr

@@ -24,6 +24,11 @@ OptionParser.parse do |parser|
     exit
   end
 
+  parser.on("-v", "--version", "show version information") do
+    puts "lx_chess version #{LxChess::VERSION}"
+    exit
+  end
+
   parser.invalid_option do |flag|
     STDERR.puts "ERROR: #{flag} is not a valid option."
     STDERR.puts parser

src/lx_chess/board.cr

@@ -1,6 +1,8 @@
 require "./piece"
 
 module LxChess
+  # A *Board* represents the squares of a chess board. it also handles coversion of
+  # indicies <=> cords. The internal representation is a contiguous array
   class Board
     include Enumerable(Piece | Nil)
 

src/lx_chess/fen.cr

@@ -3,6 +3,7 @@ require "./piece"
 require "./error"
 
 module LxChess
+  # Forsyth-Edwards Notation parser and converter
   class Fen
     class InvalidFen < Error; end
 

src/lx_chess/game.cr

@@ -5,6 +5,7 @@ require "./move_set"
 require "./error"
 
 module LxChess
+  # Represents a standard game of Chess
   class Game
     class SanError < Error; end
 

src/lx_chess/notation.cr

@@ -3,6 +3,8 @@ require "./piece"
 require "./board"
 
 module LxChess
+  # Parses Standard Algebraic Notation
+  # ex: `Pbxc8=Q` pawn on the b file takes c8 and promotes to Queen
   class Notation
     class InvalidNotation < Error; end