with.bash

$ ldd target/release/librurulol.so 
	linux-vdso.so.1 (0x00007fff13fe8000)
	libruby.so.2.3 => not found
	libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007fd16557e000)
	libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007fd165361000)
	libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007fd16514b000)
	libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fd164da0000)
	/lib64/ld-linux-x86-64.so.2 (0x00007fd165b17000)
	libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007fd164a9f000)
$ irb
irb(main):001:0> require './target/release/librurulol'
=> true
irb(main):002:0> puts Calculator.new.pow_3(5)
{1=>1, 2=>8, 3=>27, 4=>64, 5=>125}
=> nil
irb(main):003:0> 

without.bash

$ ldd target/release/librurulol.so 
	linux-vdso.so.1 (0x00007fff7946d000)
	libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f635b39f000)
	libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f635b182000)
	libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007f635af6c000)
	libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f635abc1000)
	/lib64/ld-linux-x86-64.so.2 (0x00007f635b938000)
	libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f635a8c0000)
$ irb
irb(main):001:0> require './target/release/librurulol'
=> true
irb(main):002:0> puts Calculator.new.pow_3(5)
{1=>1, 2=>8, 3=>27, 4=>64, 5=>125}
=> nil