Adding build commands

- adds mention of foss variant

README.md

@@ -16,8 +16,6 @@
 - Focused on reliability and stability.
 - Bare-bones feature set.
 
-##### _*Google play only with automatic crash reporting enabled_
-
 ---
 
 ### Feature list
@@ -29,6 +27,7 @@
 - Push notifications (DMs always notify, Rooms notify once)
 - Importing of E2E room keys from Element clients
 - [UnifiedPush](https://unifiedpush.org/)
+- FOSS variant
 
 ### Planned
 
@@ -57,4 +56,34 @@
 
 ---
 
+
+### Building
+
+
+##### Debug `.apk`
+
+```bash
+./gradlew assembleDebug
+```
+
+##### Release (signed with debug key) `.apk`
+
+```bash
+./gradlew assembleRelease
+```
+
+##### Unsigned release `.apk`
+
+```bash
+./gradlew assembleRelease -Punsigned
+```
+
+##### Unsigned release (FOSS) `.apk`
+
+```bash
+./gradlew assembleRelease -Punsigned -Pfoss
+```
+
+---
+
 #### Join the conversation @ https://matrix.to/#/#small-talk:iswell.cool