[README] Add installation and usage details of scancode_cli analyzer

Signed-off-by: inishchith <[email protected]>

Author: inishchith

README.md

@@ -49,17 +49,33 @@ For example, in Debian, likely you'll need:
 sudo apt-get install pkg-config libglib2.0-dev libjson-c-dev libpq-dev
 ```
 
-For compiling the tool (`nomossa`):
+- For compiling the tool (`nomossa`):
 
-    ```
-    $> git clone https://github.com/fossology/fossology
-    $> cd <...>/fossology/src/nomos/agent
-    $> make -f Makefile.sa FO_LDFLAGS="-lglib-2.0 -lpq  -lglib-2.0 -ljson-c -lpthread -lrt"
-    ```
+```
+$> git clone https://github.com/fossology/fossology
+$> cd <...>/fossology/src/nomos/agent
+$> make -f Makefile.sa FO_LDFLAGS="-lglib-2.0 -lpq  -lglib-2.0 -ljson-c -lpthread -lrt"
+```
 
 - **ScanCode**
 
-   Follow the instructions on the [ScanCode](https://github.com/nexB/scancode-toolkit#installation) GitHub repository
+```
+git clone https://github.com/nexB/scancode-toolkit.git
+cd scancode-toolkit
+git checkout -b test_scancli 96069fd84066c97549d54f66bd2fe8c7813c6b52
+./scancode --help
+```
+
+   **Note**: We're now using a clone of scancode-toolkit instead of a release, as the latest release is of 15th February 2019 and the `scancli.py` script (required for execution of scancode_cli) was incroporated later i.e 5th March 2019 and there hasn't been a release since.
+
+- **ScanCode Cli**
+
+After successfully executing the above mentioned steps, (if required) we have to install python modules: `simplejson` and `execnet`, for the execution of `scancode_cli` analyzer.
+
+```
+pip install simplejson execnet
+```
+
 
 ##  How to install/uninstall
 Graal is being developed and tested mainly on GNU/Linux platforms. Thus it is very likely it will work out of the box
@@ -111,6 +127,8 @@ The example below shows how easy it is to fetch code complexity information from
 requires the URL where the repository is located (_https://github.com/chaoss/grimoirelab-perceval_) and the local path
 where to mirror the repository (_/tmp/graal-cocom_). Then, the JSON documents produced are redirected to the file _graal-cocom.test_.
 
+- **CoCom Backend**
+
 ```
 $ graal cocom https://github.com/chaoss/grimoirelab-perceval --git-path /tmp/graal-cocom > /graal-cocom.test
 Starting the quest for the Graal.
@@ -121,6 +139,20 @@ Fetch process completed: .. commits inspected
 Quest completed.
 ```
 
+- **CoLic Backend**
+
+```
+graal colic https://github.com/chaoss/grimoirelab-toolkit --git-path /tmp/scancode_cli --exec-path /home/scancode-toolkit/etc/scripts/scancli.py --category code_license_scancode_cli
+Starting the quest for the Graal.
+Git worktree /tmp/... created!
+Fetching commits: ...
+Git worktree /tmp/... deleted!
+Fetch process completed: .. commits inspected
+Quest completed.
+```
+
+In the above example, we're using scancode_cli analyzer. Similarly, we can use the scancode analyzer by providing the category as `code_license_scancode` and it's corresponding executable path.
+
 ### From Python
 Graal’s functionalities can be embedded in Python scripts. Again, the effort of using Graal is minimum. In this case the user
 only needs some knowledge of Python scripting. The example below shows how to use Graal in a script.