Improve db migrations instructions

Extend existing instructions for migrating existing dB to local environment
Clarify what actions to perform on host and guest machines
Add explicit python virtualenv instructions for the non-pythonesque user

README.md

@@ -83,5 +83,34 @@ Other parameters:
 
 ## Useful commands
 
-* Copy data from an environment to the local Backdrop DB (should be run on your host machine): `cd tools; ./replicate-db.sh <youruser>@mongo-1.pp-preview`
-* Run migrations over local Backdrop DB: `python run_migrations.py`
+### Copy data from an existing to local environment
+
+**On the Host machine:**
+
+- Copy data from an existing environment to the local Backdrop dB:
+    - `$ cd <your-path>/backdrop/tools`
+    - `$ ./replicate-db.sh <your-username>@<mongo-instance-environment>` e.g. `dave@mongo-1.pp-preview`
+- Migration files are stored in the directory: `<your-path>/backdrop/migrations`	
+
+**Start and connect to the VM**
+
+- `$ cd <your-path>/pp-development`
+- `$ vagrant up`
+- `$ vagrant ssh`
+
+**On the Guest VM:**
+
+- Change to the *backdrop* directory - `$ cd /var/apps/backdrop`
+- Setup a vitual environment - [see here for more details on virtualenv](http://docs.python-guide.org/en/latest/dev/virtualenvs/)
+- *For the non-pythonesque user:* 
+    - *install virtualenv:* `$ pip install virtualenv`
+    - *create virtualenv environment:* `$ virtualenv venv`
+    - *activate the environment:* `$ source venv/bin/activate`
+    - *install any required dependencies:* `pip install -r requirements.txt`
+- Install the data - `(venv)$ python run_migrations.py`
+- De-activate the virtual environment - `(venv)$ deactivate`
+
+Done!
+
+
+