Added README, rescue from missing demo file, add .gitignore.

.gitignore

@@ -0,0 +1 @@
+*.dat

README.md

@@ -0,0 +1,15 @@
+# I-MIC FPS
+An endeavor to create a multiplayer first-person-shooter in pure Ruby; Using C extensions only for Rendering, Sound, and Input. ([Gosu](https://libgosu.org) and [opengl-bindings](https://github.com/vaiorabbit/ruby-opengl/))
+
+## Using
+Requires a Ruby runtime that supports the gosu and opengl-bindings C-extensions (truffleruby 1.0.0-rc12 did not work when tested. Rubinus was not tested.)
+* Clone or download this repo
+* `bundle install`
+* `bundle exec ruby i-mic-fps.rb [options]`
+
+### Options
+* `--native` - Launch in fullscreen using primary displays resolution
+* `--debug` - Set $debug variable to true (defaults to false)
+* `--profile` - Run ruby-prof profiler
+* `--savedemo` - Record camera movement and key events to playback later *(alpha-quality feature)*
+* `--playdemo` - Plays the previously recorded demo *(alpha-quality feature)*

lib/states/game_states/game.rb

@@ -31,7 +31,7 @@ class IMICFPS
       Light.new(x: 0, y: 100, z: 0, diffuse: Color.new(1.0, 0.5, 0.1), game_state: self)
 
       if ARGV.join.include?("--playdemo")
-        @demo_data = File.read("./demo.dat").lines
+        @demo_data = File.exist?("./demo.dat") ? File.read("./demo.dat").lines : ""
         @demo_index= 0
         @demo_tick = 0