Remove psycopg2 in package requirements #37

Why?  To leave the chose to use psycopg2-binary, psycopg2 or psycopg2cffi

Author: stephane-klein

.travis.yml

@@ -20,6 +20,7 @@ services:
 
 install:
 - pip install awscli
+- pip install psycopg2
 - pip install -r requires/testing.txt
 - python setup.py develop
 

README.rst

@@ -33,8 +33,12 @@ Queries is available via pypi_ and can be installed with easy_install or pip:
 
 .. code:: bash
 
+    pip install psycopg2-binary # or psycopg2 or psycopg2cffi (for PyPy)
     pip install queries
 
+- `psycopg2` package supported version: `>=2.5.1,<2.9`
+- `psycopg2cffi` package supported version: `>=2.7.2,<2.9`
+
 Usage
 -----
 Queries provides a session based API for interacting with PostgreSQL.

setup.py

@@ -3,11 +3,7 @@
 
 import setuptools
 
-# PYPY vs cpython
-if platform.python_implementation() == 'PyPy':
-    install_requires = ['psycopg2cffi>=2.7.2,<2.9']
-else:
-    install_requires = ['psycopg2>=2.5.1,<2.9']
+install_requires = []
 
 # Install tornado if generating docs on readthedocs
 if os.environ.get('READTHEDOCS', None) == 'True':