Added install instructions.

Makefile

@@ -1,4 +1,5 @@
 # This Makefile is only used by developers.
+# See doc/install.txt on how to install dosage
 PYTHON:=python
 VERSION:=$(shell $(PYTHON) setup.py --version)
 MAINTAINER:=$(shell $(PYTHON) setup.py --maintainer)

doc/changelog.txt

@@ -3,6 +3,7 @@ Dosage 2.12 (released xx.xx.2014)
 Changes:
 - cmdline: The --basepath option now replaces "~" or "~user" with the
   users home directory.
+- documentation: Added install instructions at doc/install.txt
 
 Fixes:
 - comics: Fix DemolitionSquad.

doc/install.txt

@@ -0,0 +1,23 @@
+Installation
+-------------
+The easy way with pip:
+
+```shell
+pip install dosage
+```
+
+You can invoke Dosage directly from the source code as
+`./dosage`. Alternatively,
+you can install Dosage using python distutils by invoking
+setup.py in the root of the distribution. For example:
+
+```shell
+python setup.py install
+```
+
+or if you do not have root permissions:
+
+```shell
+python setup.py install --home=$HOME
+```
+