Initialize Expo app structure

src/components/PrimaryButton.js

@@ -0,0 +1,34 @@
+import { Pressable, StyleSheet, Text } from 'react-native';
+
+export default function PrimaryButton({ label, onPress }) {
+  return (
+    <Pressable
+      accessibilityRole="button"
+      onPress={onPress}
+      style={({ pressed }) => [
+        styles.button,
+        pressed ? styles.buttonPressed : null
+      ]}
+    >
+      <Text style={styles.label}>{label}</Text>
+    </Pressable>
+  );
+}
+
+const styles = StyleSheet.create({
+  button: {
+    alignItems: 'center',
+    backgroundColor: '#256f5b',
+    borderRadius: 8,
+    paddingHorizontal: 20,
+    paddingVertical: 14
+  },
+  buttonPressed: {
+    opacity: 0.82
+  },
+  label: {
+    color: '#ffffff',
+    fontSize: 16,
+    fontWeight: '700'
+  }
+});