Update README.md

Author: nir0s

README.md

@@ -41,6 +41,8 @@ wagon create -s ~/modules/cloudify-script-plugin/ -o /tmp/ --pyver 33 --pyver 26
 
 Regarding exclusions, note that excluding modules can result in an archive being non-installable. The user will be warned about this but creation will succeed. Creation validation, though (i.e. using the `--validate` flag), will fail and show an error incase the archive cannot be installed.
 
+Also note that Wagon doesn't currently provide a way for packaging modules that are in editable mode.
+So, for instance, providing a dev-requirements file which contains a `-e DEPENDENCY` requirement will not be taken into consideration. This is not related to wagon but rather to the default `pip wheel` implementation stating that it will be "Skipping bdist_wheel for #MODULE#, due to being editable". We might allow processing editable provided dependencies in the future.
 
 ### Install Packages
 
@@ -57,6 +59,9 @@ wagon install -s ~/tars/cloudify_script_plugin-1.2-py27-none-any.tar.gz --upgrad
 wagon install -s http://me.com/cloudify_script_plugin-1.2-py27-none-any-none-none.tar.gz --virtualenv my_venv -v
 ```
 
+Note that `--pre` is appended to the installation command to enable installation of prerelease versions.
+
+
 #### Installing Manually
 
 While wagon provides a generic way of installing wagon created archives, you might not want to use the installer as you might not wish to install wagon on your application servers. Installing the module manually via pip is as easy as running (for example):