chore: fix install instructions in readme, .gitignore venv / secret.txt (#68)

.gitignore

@@ -7,9 +7,10 @@ Session.vim
 /.coverage
 /tmp
 /media
+/.idea
 
 __pycache__
 .*.swp
 
-
 /etebase_server_settings.py
+/secret.txt

README.md

@@ -23,11 +23,10 @@ Then just clone the git repo and set up this app:
 git clone https://github.com/etesync/server.git etebase
 
 cd etebase
-git checkout etebase
 
 # Set up the environment and deps
-virtualenv -p python3 venv  # If doesn't work, try: virtualenv3 venv
+virtualenv -p python3 .venv  # If doesn't work, try: virtualenv3 .venv
-source venv/bin/activate
+source .venv/bin/activate
 
 pip install -r requirements.txt
 ```