add README.md: provide documentation for dynamic array library

Makefile

@@ -1,11 +1,16 @@
 .PHONY: configure build clean test install
 
+# Lib
+LIB_NAME := dynamic_array
+
 # Build directory
 BUILD_DIR := build
 
 # Default target
 .DEFAULT_GOAL := help
 
+INSTALL_PREFIX ?= ~/.local/bin/$(LIB_NAME)
+
 
 # Help target
 help:
@@ -35,5 +40,5 @@ test: build
 
 # Install: Install the library
 install: build
-	cd $(BUILD_DIR) && cmake --install .
+	cd $(BUILD_DIR) && cmake --install . --prefix $(INSTALL_PREFIX)