Added Android installation documentation.

Author: xvitaly

docs/README.md

@@ -5,6 +5,7 @@
   * [PyPI installation](pypi-installation.md)
   * [System installation](system-installation.md)
   * [Virtual environment installation](virtualenv-installation.md)
+  * [Android installation](android-installation.md)
   * [Fedora installation](fedora-installation.md)
   * [Windows installation](windows-installation.md)
 

docs/android-installation.md

@@ -0,0 +1,14 @@
+# Android installation
+
+  1. Use [F-Droid](https://f-droid.org/) to download and install the following packages:
+    * [com.termux](https://f-droid.org/packages/com.termux/);
+    * [com.termux.api](https://f-droid.org/packages/com.termux.api/).
+  2. Open Termux and install `termux-api` package:
+  ```
+  apt install termux-api
+  ```
+  3. Install Python interpreter:
+  ```
+  apt install python
+  ```
+  4. Follow the standard installation procedure: [VENV](virtualenv-installation.md) or [PyPI](pypi-installation.md).