Add a subsection on documenting the --no-root option in the Basic Usage section…

Add a subsection on documenting the --no-root option in the Basic Usage section and also in the CLI. Resolves #1848.

docs/docs/basic-usage.md

@@ -134,6 +134,15 @@ the dependencies installed are still working even if your dependencies released
 
     For libraries it is not necessary to commit the lock file.
 
+### Installing dependencies only
+
+The current project is installed in [editable](https://pip.pypa.io/en/stable/reference/pip_install/#editable-installs) mode by default.
+
+If you want to install the dependencies only, run the `install` command with the `--no-root` flag:
+
+```bash
+poetry install --no-root
+```
 
 ## Updating dependencies to their latest versions
 

poetry/console/commands/install.py

@@ -34,6 +34,12 @@ libraries and dependencies outlined in that file. If the file does not
 exist it will look for <comment>pyproject.toml</> and do the same.
 
 <info>poetry install</info>
+
+By default, the above command will also install the current project. To install only the
+dependencies and not including the current project, run the command with the
+<info>--no-root</info> option like below:
+
+<info> poetry install --no-root</info>
 """
 
     _loggers = ["poetry.repositories.pypi_repository"]