Add a precommit script (#372)

Add a script to run before the commit to make sure that the correct
formatting is applied, the unit tests are successful and the dist is
building successfully.

Author: dawidxc

precommit.sh

@@ -0,0 +1,62 @@
+#!/bin/bash
+
+set -e
+
+STEP_FORMAT=false
+STEP_TEST=false
+STEP_BUILD=false
+
+if [[ $# -eq 0 ]] ; then
+  STEP_FORMAT=true
+  STEP_TEST=true
+  STEP_BUILD=true
+else
+  while [[ $# -gt 0 ]]; do
+    case $1 in
+      -f)
+        STEP_FORMAT=true
+        shift
+        ;;
+      -t)
+        STEP_TEST=true
+        shift
+        ;;
+      -b)
+        STEP_BUILD=true
+        shift
+        ;;
+      -h)
+        echo "Command to perform precommit actions."
+        echo
+        echo "Usage: precommit.sh [-f] [-t] [-b]"
+        echo
+        echo "If no option is specified, then all actions are executed."
+        echo
+        echo "Options:"
+        echo "  -f format the files"
+        echo "  -t run unit tests"
+        echo "  -b build the dist"
+        exit
+        ;;
+      *)
+        echo "ERROR: Unknown option '$1'."
+        exit 1
+        ;;
+    esac
+  done
+fi
+
+SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
+GRADLE_CMD="$SCRIPT_DIR/gradlew"
+
+if [[ "$STEP_FORMAT" == "true" ]] ; then
+  "$GRADLE_CMD" spotlessApply
+fi
+
+if [[ "$STEP_TEST" == "true" ]] ; then
+  "$GRADLE_CMD" :dumper:app:test
+fi
+
+if [[ "$STEP_BUILD" == "true" ]] ; then
+  "$GRADLE_CMD" --parallel :dumper:app:installDist
+fi