Added README for 2015 and edited root README

2015/README.txt

@@ -0,0 +1,37 @@
+                          ___________________
+
+                           README - 2015 AOC
+                          ___________________
+
+
+From 01/11/2024 to 30/11/2024 I will be attempting to finish 2015's
+advent of code in preparation for 2024's AOC.
+
+I _should_ spend at most one day per challenge but I refuse to use
+external solutions so I may spend more time on each challenge, hence the
+deadline being 30/11 rather than 25/11.  Of course, I am not restricting
+myself to doing one challenge a day - that would be a waste of my time
+considering they're all released.  I doubt, however, that I'll be able
+to finish _earlier_ than my deadline.
+
+I want to do this advent of code in more than one language if possible.
+Here is a list of all the languages I am aware of enough to program in,
+ordered from least to most confidence:
+
+- (0) POSIX Shell
+- (0) Haskell
+- (0) Ocaml
+- (0) Rust
+- (0) Racket
+- (0) JavaScript/TypeScript
+- (0) Common Lisp
+- (0) C
+- (0) Python
+- (0) C++
+
+On the left of each language, in brackets, is a list of all the
+challenges I've solved in the corresponding language.  My hope is to
+have used each language in at least one challenge.  My thinking is that
+due to the earlier challenges being easier to solve I'll go down the
+list linearly.  When I get past challenge 10, I get to freely choose
+what language I use to solve the problem.

README.org

@@ -2,5 +2,4 @@
 #+author: Aryadev Chavali
 #+date: 2023-10-17
 
-My solutions to the advent of code for each year.  I dunno what
-languages I'll use per year ngl.
+My solutions to the advent of code, organised by year.