Added note on installation

Iain Bancarz · Iain Bancarz · commit efb1452d300a · 2013-01-11T15:12:47.000Z
diff --git a/README.txt b/README.txt
@@ -2,6 +2,10 @@
 This is a development fork of the gftools library. The repository at
 http://gftools.sourceforge.net/ is no longer maintained by the author.
 
+Installation:
+make install PREFIX=<install-directory>
+
+
 Gftools requires the Plink software package.
 See http://pngu.mgh.harvard.edu/~purcell/plink/
 
