assign sfinae is integral detection

Makefile

@@ -32,7 +32,7 @@ RESET    = "\e[0m"
 
 NAME          = containers
 
-CC            = c++
+CC            = clang++
 EXT           = cpp
 
 CFLAGS        = -Wall -Wextra -Werror $(INCLUDES)
@@ -55,6 +55,7 @@ SRCS          = main.cpp
 D_HEADERS     = ./headers
 HEADERS       = colors.h \
 				tests.hpp \
+				enable_if.hpp \
 				vector.hpp
 
 D_TEMPLATES   = ./templates