Update documentation

README.md

@@ -4,9 +4,23 @@ Minisign
 
 Minisign is a dead simple tool to sign files and verify signatures.
 
-For more information: https://jedisct1.github.io/minisign/
+For more information, please refer to the
+[Minisign documentation](https://jedisct1.github.io/minisign/)
 
 Tarballs and pre-compiled binaries for Windows and OSX can be verified with
 the following public key:
 
     RWQf6LRCGA9i53mlYecO4IzT51TGPpvWucNSCh1CBM0QTaLn73Y7GFO3
+
+Compilation / installation
+==========================
+
+Dependencies:
+- libsodium
+- cmake
+
+    $ mkdir build
+    $ cd build
+    $ cmake ..
+    $ make
+    # make install