Documentation update about editable mode (#703)

* Add info about path dependencies being installed in editable mode
according to information here:
https://github.com/sdispater/poetry/issues/519#issuecomment-440028167

* Fix missing verb in doc

Co-Authored-By: germn <germn@users.noreply.github.com>

docs/docs/cli.md

@@ -177,6 +177,16 @@ poetry add my-package --path ../my-package/dist/my-package-0.1.0.tar.gz
 poetry add my-package --path ../my-package/dist/my_package-0.1.0.whl
 poetry add my-package --path ../my-package/dist/my_package-0.1.0.whl
 ```
 ```
 
 
+Path dependencies pointing to a local directory will be installed in editable mode (i.e. setuptools "develop mode"). 
+It means that changes in the local directory will be reflected directly in environment.
+
+If you don't want the dependency to be installed in editable mode you can specify it in the `pyproject.toml` file:
+
+```
+[tool.poetry.dependencies]
+my-package = {path = "../my/path", develop = false}
+```
+
 ### Options
 ### Options
 
 
 * `--dev (-D)`: Add package as development dependency.
 * `--dev (-D)`: Add package as development dependency.